Its lacquer coating that you applied on the furniture can chip and display discolored material beneath the coating. For restoration purposes, the only distinction that really matters is the difference among the three basic natural, or. How to repair acoustic guitar finish guitar repair bench. This problem can usually be fixed when the finish is shellac or lacquer, but repairing cracking or crazing varnish is usually more difficult if not impossible. I wouldnt use lacquer to do the repair because the thinner will also soften the original lacquer finish. If lacquer thinner softens the finish, it is lacquer. How to repair catalyzed wood finishes woodworking network. This is an extremely common, somewhat expected condition on older instruments with lacquer finishes. The simple repair were about to do is called a dropfill. Finish crack in polyurethane how to repair the gear.
The reason why the cracks feel smooth on the outside of the guitar is because the lacquer is cracking from the. In most situations, cracking and crazing occur when the furniture finish has been exposed to one of several conditions of if the finish was mixed or applied incorrectly. Take each door with damaged finish down, remove all the hardware with a screwdriver. To my eyes your guitar looks like finished with a tinted coat. One of the most disappointing of those is the tendency to check or crack with a. Once the crack is glued and cleated the next step is finish touchup. John also authored pgs guitar shop 101 column, hosted several pg diy videos, and is an authorized warranty technician trainer for taylor guitars. Identifying a shellac finish can be difficult, however, and if you repair a nonshellac surface by laying shellac over the top of the finish, it will not produce good results.
However, you can put enamel over lacquer without it attacking the lacquer. However, a skilled, experienced luthier should be able to do a finish repair without making the guitar looking blotchy. Lacquer comes in a variety of colours, and if you have furniture finished with black lacquer you may notice that scratches, dings and dull spots are painful evident under direct lighting. May 28, 2008 i put a scratchcrack through the lacquer finish of my johnson jo27 with a bridge pin puller.
Alligatoring, crazing, and cracking are all basically the same thing. Avoid cracks by insuring your instrument is properly humidified and well. If that happens, restore a satin sheen by rubbing with extrafine 0000 steel wool and paste wax. When the process is done correctly, the outcome can be a finish that looks like new. The lacquer has checked all over, but the neck is the most severely affected, with the finish actually beginning to lift and fall off. For this reason small chips, sink marks and cracks can.
I have finished a lot of ebony before without the crystalac without any problems so i tend to suspect the crystalac which was applied heavier to the ebony. In the worst case scenario, the problem must be fixed by completely refinishing the piece of furniture. Id say it has been subjected to extremes of temperature and humidity. Spray a full wet coat of lacquer on the door, using either a compressed air spray gun or an aerosol can. After dan repaired a crack in a gibson acoustic guitar the finish didnt look. How to repair the black lacquer finish on a piano our pastimes. After determining the type of finish you are working with, remove all of the hardware and decorative materials. If it has a cracked appearance all over it like spider webs, then as mentioned above you have whats called a checked finish, this occurs from nitrocellulose lacquer being used and an extreme of heat or cold has happened on the instrument, also checking happens with nitro as it ages. Apply a coat of the lacquer over the area being repaired and then wait for five minutes. This sample shows a finish that is marred by checking.
Car paintwork damage, while annoying, can be taken care of fairly easily and quickly all you need is a paint touch up kit from chipex and youre good to go. Repairing cracked lacquer varnish on doors home guides. Spray a wet coat of pure lacquer thinner on a surface that has cracks, orange peel or roughness. Roy is rightlacquer thinner will rewet the lacquergood news if you know how to make it work for you to blend in new lacquer but bad news when things start going south on you. Theres a difference between car paintwork needed to be repaired and car lacquer needing to be repaired. Lacquer drop fills on lacquer on the other hand have the potential to melt into the old finish because the solvent partially redissolves the surrounding finish.
If you own an acoustic guitar long enough, chances are good that youll have to deal with the repair of a crack in the wood. The original surface is wood that was painted, then finished. Modern polybased guitar finishes are hard plastic, and when theyre damaged, pieces fall off. Fine lines and cracks in the finish can be fixed by using a fine paintbrush dipped in lacquer thinner. I recently bought a used epiphone zephyr regent jazz box, and found two very thin hairline cracks in the polyurethane finish right by the nut where you would hang the guitar. However, issues such as scratches in a pianos black lacquer surface finish can easily be resolved at home and can save the owner thousands of dollars in repair fees and expenses. The thin, watery superglue will fill cracks in lacquer pretty well. Checking will vary according to the extremes the instrument has been through. Not sure how to repair without removing the entire finish down to the wood. One of the mandolins has a light, almost maple like, finish and the webbing shows well.
Start by removing all of the dust from the affected area using. While reinstalling this pickup mounting ring, a stubborn screw made the screwdriver jump onto the top. The new lacquer would tend to melt right into the old, but having amalgamated the area, i was certain that id get a seamless weld between the new and old finish. Most services that are required in order to maintain a piano are simply too complicated for an owner to deal with himself. The three finishes you are most likely to encountershellac, lacquer and polyurethanecan be identified by simple tests on an inconspicuous spot on the piece. This editorial will provide with some tips and information on how to repair damaged lacquer.
Im pretty sure the jo27 has a nitrocellulose lacquer finish. Test the finish to make sure it will soften before you try to repair it. I decided to rub out the finish on the telefunken jubuilate 5161w im working on. If i put a new clear finish on it i suspect all i will have accomplished is making the crackleswebbing bright and shiny.
Special repair materials, equipment and procedures are required to make polyester repairs. Start by using a 400wd sandpaper to sand out the lines. We bought this from john lewis so maybe they can tell us. How to repair the black lacquer finish on a piano our. In the effort to revive a more severely degraded finish, such as one that has crazing or wrinkling, varnished and lacquered surfaces need to be approached differently. Wax precleaner is a substance which can be found at many auto repair. Bleed the air lines of the spray gun and wipe moisture from the tip if. Let it dry, and afterward, apply paste wax to the area and buff it.
Nitrocellulose laquer finish repair the unofficial martin. The repair procedure works best if you lay the door flat and. Black rings indicate damaged wood and require complete removal of the surrounding finish before any repair can be attempted. I cant tell from the picture if color touch up will be needed or if there is any indentation in the wood. This is done by the application of the appropriate. Using a finepoint artists paintbrush, paint in the grain marks to match the rest of the wood on the product. How to repair lacquer when you choose to use lacquer finishes on your wooden furniture, it is for the purpose of creating a more elegant and classy look of the furniture, plus also enhanced the furnitures toughness, durability and also water resistant.
I usually dont recommend trying to fix such checks, because they are often an inevitable part of. Generally this will be the most expensive part of the repair because it is very time intensive. For example, the scratch on this gorgeous les pauls birdseye maple top. Repairing a damaged finish hide blemishes without refinishing. Antique radio forums view topic repairing cracked lacquer. The thinner will emulsify the surface and the defects should. Lacquer is very high in solvents and it shrinks quite a bit. This makes a repair a little more difficult compared to a stained, clearcoated top. What kind of stain, sanding sealer, and finish coat did you use on the original finish, and did they change on the refinish. Add a retarding agent to the thinner to correct blushing, a condition whereby trapped moisture. The finish consisted of a one coat of bullseye sealcoat,crystalac grain filler, and sherwin williams nitrocellulose lacquer. The problem is that while this is often seen as a durable material, lacquer can quite easily get chipped, scratched, and cracked over time. There doesnt appear to be a crack in the wood, but i can feel. Touch up refers to techniques used to repair and disguise damage on already finished woodwithout refinishing.
It is not that difficult for you to repair the damage on your lacquer that you applied on wooden furniture. Mix a new batch of lacquer that is in a ratio of two parts lacquer and one part thinner. A repair magnet in the bottom of the cup holds it to the metal lacquer can so it wont spill. Repairing cracks in acoustic guitars examples of cracks caused. Mix powder and lacquer as before, but use twice the amount of dark powder to achieve a darker coloured lacquer. Now that you have a clean and scratch free finish you can concentrate on filling the cracks.
How to repair a lacquer finish home guides sf gate. Moose was real clear in stating that he sanded back to bare wood, then restained, applied sanding sealer, and then three 3 coats of lacquer, and now, the daggone cracks are back. What is the best way to repair damaged car lacquer. You cant put lacquer over enamel or other materials because the thinner in lacquer will attack most other finishes except epoxy. To repair these cracks the stress must be eliminated by removing the pickguard and reattaching or replacing it. When repairing lacquer finishes a new lacquer fill is placed in the finish crack. In cases where the original finish is lacquer or shellac, its possible to save the finish through a repair technique called reamalgamating. It can be fixed, but it will take someone who knows how to repair lacquer. If the finish did not soften with either denatured alcohol or lacquer thinner, it is probably varnish or a penetrating oil finish. Because lacquer and shellac form a film through evaporation of the solvents, and no crosslinking takes place, they can be redissolved and flowed out using the proper solvents. It can be resurfaced and buffed over real nicely too. There are a few methods you can follow to repair the black lacquer and return it to its original beauty. How to repair lacquer on table moneysavingexpert forum.
Aug 14, 2011 restoring checked and crazed finishes. How to repair a crack in a lacquer finish know about life. It mainly depends on what compound was used to finish your kit. Knowing how to evaluate the seriousness of a crack will allow you to determine whether to call a repair person immediately or whether it might be ok to leave it alone for a little while. Modern lacquer consists of a resin called nitrocellulose and a. The part ive done so far looks really good, except the area at the top right where the lacquer has cracked. If your kit was sprayed with acrylic or nitrocelluloselacquer then the finish can be repaired easily by dissolving the old lacquer into new lacquer together as the solvent. Fixing cracking and crazing is easier with some wood finishes than others. Lacquer finish wood furniture is becoming popular once again. Lubricate a sheet of 400grit wetdry sandpaper with water and rub the finish to. Some describe cracking and crazing on wood finish as looking like a spider web inside of the finish or like the segmented skin that you might see on an alligator. How to repair a crack in a lacquer finish step 1 clean the area. In an effort to avoid a repeat, and keep the new adhesive from pulling up wood fibers if removed again, this bare area of wood beneath the guitar is usually sealed with finish. Nitrocellulose laquer finish repair the unofficial.
The next day, i brushed in another stripe of lacquer, so that id be sure the filled area would be higher than the original level after the lacquer dried. How to repair a lacquer finish spray a wet coat of pure lacquer thinner on a surface that has cracks, orange peel or roughness. Dang i had a feeling it might not be a quick repair job i have no idea what the finish is i just assumed it was either oil wax or lacquer it doesnt rub off so i guessed lacquer. This lacquer fill will begin to shrink almost immediately and a small depression is likely to appear, even after weeks of patient waiting. The first step in making a repair is to clean the surface with mineral spirits. The whole idea here is to dissolve the finish enough to soften it and cause it to get really sticky so it will fall back to the surface of the wood and stick just the way. A brand new piece of lacquered furniture looks amazing, but over time they can start to. A professional could make this almost completely invisible.
The solvent causes the finish to soften, and rubbing the solvent with the pad encourages the finish to redistribute into a smooth texture. Blend new lacquer into old lacquer with flash coats youtube. Restoring checked and crazed finishes woodworking network. Many other finishes resemble shellac, and to further add to the confusion, shellac is sometimes used as a generic term referring to any clear top finish. The basic idea in reviving a lacquer finish is to soften the finish so that the surface imperfections level out and heal. This week my buddy kevin kamberg, an expert in using mek and pm acetate to repair wood finishes, gives a few tips.
The coat should be thick enough to be visibly liquid and to. The glossy look of lacquer is seen as very fashionable. A lacquer finish is more brittle and prone to cracks than varnish or polyurethane, but the good news is that the cracks are repairable. As an instruments wood expands and contracts with moisture content stress is placed on the finish. How to repair a crack in a lacquer finish lacquer is the most commonly used finishing product for both wood furniture and guitars. How to repair cracks in your acoustic guitar guitar alliance. While im not opposed to accumulating some mojo on this guitar, id also be up for some technical experimentation id never. One of the most disappointing of those is the tendency to check or crack with a sudden drop in temperature. I had a feeling it might not be a quick repair job i have no idea what the finish is i just assumed it was either oil wax or. The checks appear slightly whitish as though the lacquer cracked.
John levan has written five guitar repair books published by mel bay. I put a scratchcrack through the lacquer finish of my johnson jo27 with a bridge pin puller. If a cotton ball dipped in denatured alcohol softens the finish, it is shellac. Repairing cracked lacquer varnish on doors home guides sf. Repairing cracking and crazing furniture finishes furniture. While im not opposed to accumulating some mojo on this guitar, id also be up for some technical experimentation id never try on my martin. For restoration purposes, the only distinction that really matters is the difference among the three basic natural, or clear, finishes. May 17, 20 razor blades can help in catalyzed wood finish repair.
If neither solvent affects the finish, it is polyurethane. It is very durable and adds a nice sheen to the object its applied to. Empty the spray gun and fill it with this new mixture. Clear or solid high gloss black polyester finishes on pianos magnify the wood grain and bring to life the finished surface in a way that lacquer can not do. Dont forget that acetone nail polish remover is your best remedy for getting your fingers unstuck with crazyglue. Retarder thinner is added to lacquer to slow the drying time. Theres a specialty finish called crackle lacquer thats designed to produce cracks for the visual effect. Nitrocellulose lacquer does have some nasty habits. Use extra care not to sand off any color that may be in the coating or any stain in the wood. The finish on both shows spiderwebbing or crackling.
To bring back a gloss finish, use auto polishing compound applied with a rag. Repair of high gloss polished polyester lacquer finishes. These days polyester lacquer has pretty much vanished from the marketplace. The solvent will work with the lacquer to level it out. And on vintage instruments, finish repairs may actually diminish the value of the. Reamalgamation of an old finish how to restore wooden.
It is a time consuming process to repair these finishes to their strong brilliance and luminosity. You can see a couple of places where the finish is missing at the edge by the fourth string tuner. This made a nasty scratchdent combo right where it shows. Since the finish is lacquer, then water, mineral spirits, even a light furniture polish or a paste wax might be used as the lubricant. Unlike varnish or polyurethane, lacquer doesnt cure after. With a small artists brush, i place a drop of acetone on the dent to soften it and prepare it to accept a drop of lacquer. Lacquer repair after sufficient drying, we turn to the repair of the lacquer finish. Depending on the value of the instrument, this work may not be cost effective. After five minutes have passed, add another layer of lacquer. If the sheen to the finish is flat, then it will be necessary to rub it out using the black, wetdry abrasive paper such as might be used on automobiles. Reamalgamation is a grand revival technique that can make alligatored, crazed, cracked, and scratched furniture look like new. Fixing crack in the lacquer the steel guitar forum.