Tenite Deep Gouge Repair with Acetone

[WEBellSystemChristian]

Here's another option to repairing deep gouges in Tenite without either heavy sanding or trashing the part. This housing had a patch of very deep gouges (much deeper than they appear to be in the pictures, maybe 1/16 of an inch in most areas) in the cradle area, most likely from someone desperately trying to remove a sticker (I'm afraid to find out what with).

The Acetone and Denatured Alcohol I used for this were by Kleanstrip; I don't know how widely the chemicals vary with other companies.

[WEBellSystemChristian]

I used a glass dropper to drip Acetone into the gouges. Acetone is strong enough to 'lift' the low spots in the plastic, eventually pulling the gouge level with the rest of the plastic. Although Acetone evaporates very quickly, don't blow on it; allow it to air dry at its own pace. Do this in several passes, until the gouge(s) seems to be gone.

After allowing the Acetone to fully evaporate, wetsand the area with 800 grit until smooth. If the gouge still seems evident, add another drop of Acetone, wetsand, and repeat (if necessary) until even.

[WEBellSystemChristian]

 **If you are uncomfortable with the following step, simply use 2000 or higher grit sandpaper instead of Denatured Alcohol, followed by polish**

When surface is even, use a saturated paper towel with Denatured Alchohol to polish the surface. Don't let the Alcohol fully evaporate before you stop polishing, stop while the surface still has a 'wet look' from the alcohol. Let air dry, and repeat. When you believe the surface is free of scratches from 800 grit, start polishing with Novus or what you normally use for polish. If surface still has scratches, use Denatured Alchohol followed by polish again.

This is just another alternative for removing deep scratches that I tested tonight. I could have been more thorough with the process (and I will as restoration for this phone continues) but it clearly seems to work very efficiently, and seems to be a better process by re-forming plastic rather than removing it to get rid of scratches.

As for Denatured Alcohol, I use it regularly for polishing minor imperfections and 'hazing' out of Tenite.

[Pourme]

That is interesting, Christian. Thanks for the info and pics!

[TelePlay]

That is an interesting variation on a theme that can be found in several other topics on the forum. Since this is a new topic and some newer members may not be aware of past discussions, I've linked to several below.

Chuck (cihensley) did a lot of work on this type of repair in quite a few topics but never came up with that technique. This is one of those topics I remember because I posted in it about a tough paper with tooth that I found useful in chemical sanding, using a mixture of various solvents plus water to control the rate of removal.

http://www.classicrotaryphones.com/forum/index.php?topic=10318.0

For reference, this is a topic started by Chuck what used an acetone dip process on hard plastic and the topic has other links within to forum topics.

http://www.classicrotaryphones.com/forum/index.php?topic=5260.0

and this one

http://www.classicrotaryphones.com/forum/index.php?topic=5030.0

Historically, WE provided a bottle of chemical solvent for "freshening up" phones in the field

http://www.classicrotaryphones.com/forum/index.php?topic=14068.0

Back then, I did an experiment with a strong solvent on textured ABS which lasted only a few seconds and that was posted there. You can see what a solvent on an uneven surface does to "smooth out" that surface. I think this is similar to what was done here except acetone is a less harsh solvent than what I used.



Much of the stuff posted to date was surface or spot repair which differs from this new technique. It seems drastic but it turned out well for you. It's another tool in the arsenal of surface repair, one I need to be practice on junk plastic before I try it on a good housing.

Using a solvent to "raise" a scratch is novel and I was wondering if you looked at the "raised" scratch to see if it did raise or was filled in by the surrounding areas leaving a very small "dip" which can be wet sanded smooth to invisibility.

Overall, good work.

[WEBellSystemChristian]

I think the Acetone may do a bit of both.

I know that the gouges were really deep, and there was absolutely no way of sanding them out, not even with 80 grit. It is possible that the Acetone 'knocks down' the high points to fill in the low points, but either way, you can't tell after it's polished.

After I posted those pictures, I added very small drops to a couple craters that were left, but this resulted in larger yet more shallow craters. That's probably the Acetone 'borrowing' higher surrounding plastic to fill in that divet. I knocked those larger craters down with Sunnyside Laquer Thinner (yep, one more chemical to use) and sanded with 800 grit and will follow up with Denatured Alcohol and polish.

PS, another thing to watch out for is keeping your fingers free of wet chemicals while polishing. I accidentally got still-liquid lacquer thinner on my finger, which I used to grip the housing with. Whoops! No problem, it'll come out with Denatured Alcohol!

[TelePlay]

Good info, and the only thing worse than solvent on a finger applied to plastic is water thin super glue on a finger that then touches anything (which necessitates another good use for acetone, removing the item from the finger . . .  )

[WEBellSystemChristian]

Here's how it looks after a complete buffing with Denatured Alcohol followed by polish. Besides the gouges in the cradle, this housing was hazed and scratched so badly that there was no way it would polish out with abrasives; was ready to toss it. I guess it could look a little better, and by a little better, I mean 100% NOS!

I highly recommend the Denatured Alcohol method for pre-polishing Tenite. This works for plastic 302s and Tenite 500s, both in black and color. Beware, I have found that color Tenite on 500s is more affected by the alcohol, so don't buff it as much as you would with black, simply let the surface get a 'wet' look and let it evaporate. Try it on scrap pieces first for practice before using it on a real showpiece.

[Pourme]

That cane out really good, Christian! From ugly duckling to show piece!