KelvinS1965

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So I picked up some of this today and have applied 3 coats. How many coats would you say is enough to check? As stated above, this is a free project so want to save on materials as much as possible

I don't know. As I said before I haven't tried checking my Strat body that I sprayed with it, I'm just leaving it to let it go naturally (or not). In some ways I'd have thought more coats would then be more likely to crack, but seeing Preacher's post above I wonder if it will ever crack (beyond just straight chipping) if there is poly under the nitro.
 

ratylird

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This^^^

If the body is poly you are probably never going to get it to check. And spraying nitro over poly is probably not a great idea to see some checking either. Checking occurs when the body wood shrinks or expands quicker than the nitro finish. With the poly finish over the body, the body can contract and the poly will hold its shape pretty well through the heat and the cold. I would describe it like a sock on your foot, you can move your toes around and not really change the shape of the sock.

I tried acetone and it’s definitely nitro. The guy who I’m doing it for said that the guy he purchased it off said that the base coat was a poly nitro mix with nitro over the top.

I’m guessing it can be done as fender-guy pointed out here. Though I assumed it would have checked regardless of adding more to it :/

I suspect what was already mentioned is that if it’s a type of nitro that hasn’t fully hardened or cured it will not check. If it’s even nitro. I’ve done this sped up checking a lot and never had a issue with compressed air upside even with heat.

The only time I’ve had it melt back together was on a newer American Original 60’s Strat neck. Compressed air would do it but a few seconds later 80% of the checking melted back together.

Here’s my 80’s Fullerton 57 body, naturally aged with its nitro over polyurethane. If it’s actual hardened/cured nitro over poly you should have no problem forcing it to check. View attachment 874560
 

Boreas

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"Aging" a modern guitar body often turns into a the look of a "poorly finished" or abused guitar instead of natural wear and tear on a properly finished old nitro guitar. I personally don't like the look of a relicked guitar, and it wouldn't increase its value to me. I may be alone in this thought, but I have several guitars in excess of 40 years old that with a little spit and polish would look almost new. I also have old Gibsons that have checked dramatically and they look great. My Martins tend to wear more than check, but they look great as well. My 74 Thinline (heavy poly) looks like glass and a disco era bartop. I don't care for that look, but I would never change it. It is a product of its era.I have even been known to (gasp!) clean and polish a guitar or two.

I have considered damaging a couple new Squiers to give them a relicked look, but as far as I am concerned, it limits their resale even more. Not everyone likes the look, but most people like the look of an unmolested or naturally-worn guitar, whatever the age or brand.

But I wish the OP luck in his pursuit of finish checking if that is what his friend wants. I think much of this is a reflection of age. When you get to be my age, you have about had it with deterioration. Speeding it up doesn't make allotta sense to me. I am just an old man shouting at kids to get off my lawn...
 

VWAmTele

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I've been waiting almost 50 years for my '72 LP Deluxe to check (actually I didn't know what 'checking' was until the internet). It had been used and abused over the years but still no checks.

upload_2021-7-7_13-25-40.jpeg
 

old wrench

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Speaking as an observer :)

It's a strange world where on the same forum you have people concerned that their finish has checked, and you also have people concerned that their finish has not checked ;).

.

.
 

Danb541

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I had a guitar check when I wasn't even trying, it checked so much it's ridiculous. A pine body, base coat is rattle can zinsser bulls eye shellac. Top coats are rattle can nitro, woodcraft brand "touch up solutions toner-dye". After shellacking, the body probably sat a week. I then sprayed it and accidently left it in the garage over night. The temp was around freezing. When I looked at the guitar the next morning it was extremely checked.
Perhaps a shellac undercoat is the way to go, I have no idea.
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Boreas

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I had a guitar check when I wasn't even trying, it checked so much it's ridiculous. A pine body, base coat is rattle can zinsser bulls eye shellac. Top coats are rattle can nitro, woodcraft brand "touch up solutions toner-dye". After shellacking, the body probably sat a week. I then sprayed it and accidently left it in the garage over night. The temp was around freezing. When I looked at the guitar the next morning it was extremely checked.
Perhaps a shellac undercoat is the way to go, I have no idea.
View attachment 875215 View attachment 875216 View attachment 875218 View attachment 875219 View attachment 875220

Checking, alligatoring, and edge wear - the trifecta! Chipping would get you the grand slam!
 

Peegoo

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You are working backwards.

The way to artificially check nitro is to rapidly cool it while it's warm.

The mechanism at work is a warm body/finish is in an expanded state, and then a rapid cooling of the surface finish causes it to shrink slightly, checking the finish.
 

ratylird

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You are working backwards.

The way to artificially check nitro is to rapidly cool it while it's warm.

The mechanism at work is a warm body/finish is in an expanded state, and then a rapid cooling of the surface finish causes it to shrink slightly, checking the finish.

That was my first attempt with heating it with a heat gun and using canned air, but that didn’t work. When I searched online I saw people mention sticking it in the freezer over night, that didn’t work either.

my main question is if it didn’t check before, is there more of a chance of it checking now that I’ve added more clear nitro, or am I just wasting my time?
 

Peegoo

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That was my first attempt with heating it with a heat gun and using canned air, but that didn’t work. When I searched online I saw people mention sticking it in the freezer over night, that didn’t work either.

my main question is if it didn’t check before, is there more of a chance of it checking now that I’ve added more clear nitro, or am I just wasting my time?

Warming the finish with a heat gun is not going to work. You need to heat up the entire body, including the internal wood. Some folks stick it in the oven at 150F-175F for about an hour and then shwack it with component freeze spray or stick it in the freezer. The crazing of the finish occurs almost instantly...not overnight.
 

4pickupguy

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Make sure the finish is fully cured by putting it under a heat lamp and letting it gently warm for a day or two. Nitro has solvents that evaporate away. For checking, I have had good results from using dry ice. Start on the back. If you get to an area that wants to be stubborn, gently rap it with a blunt, hard object like a screwdriver handle. Apply dry ice to the area of the small dent and it will ‘shatter’ emanating from the dented (stressed) area.
 

DrASATele

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You are working backwards.

The way to artificially check nitro is to rapidly cool it while it's warm.

The mechanism at work is a warm body/finish is in an expanded state, and then a rapid cooling of the surface finish causes it to shrink slightly, checking the finish.

Winner winner!...lol....
Take the body outside into the hot air (85 & up) for 10 15 min, no direct sunlight though. Then about 2-3 minutes in the freezer. The issue that can cause this not to work is humidity, the dryer the better.
 

ratylird

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Winner winner!...lol....
Take the body outside into the hot air (85 & up) for 10 15 min, no direct sunlight though. Then about 2-3 minutes in the freezer. The issue that can cause this not to work is humidity, the dryer the better.

i live in England, it’s always raining haha
 




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