Masking tape under pickguard

[PunchyStrummer]

Hi all,

I took off the pickguard of my 1988 330 and I saw strips of masking tape between the pots and the pickguard - what is the purpose of this tape?

Also, it was starting to weaken, so I peeled it off - what's the best way to remove the residue?

[jps]

Hi all,

I took off the pickguard of my 1988 330 and I saw strips of masking tape between the pots and the pickguard - what is the purpose of this tape?

Also, it was starting to weaken, so I peeled it off - what's the best way to remove the residue?

You're removing the vintage mojo by doing that. Put the old, original pickguard in a safe place and get a repro guard made by Pickguardian to put on the guitar.

[PunchyStrummer]

I'm sorry, are you referring to removing the tape? It was starting to come off slightly anyway but I could always put new strips on... especially if it's meant for shielding.

[jps]

Oh, in that case I suppose you could replace the tape. Clean off all the old residue with naphtha before applying the new tape. That tape was standard procedure on vintage Ricks. That is no longer done (not sure when they stopped doing so).

[PunchyStrummer]

I see. Thanks for the info. Considering that masking tape isn't considered shielding material I don't think I'll work out what exactly it's for...

[jps]

I believe it was to prevent cracking of the pickguard material (minimizing the chance of that occurring, anyway), either when drilling the holes for the components, or when tightening the components down on it.

[Ontario_RIC_fan]

I believe it was to prevent cracking of the pickguard material (minimizing the chance of that occurring, anyway), either when drilling the holes for the components, or when tightening the components down on it.

Yup, that is what I thought too. The tape was to keep the plexi from cracking when they drilled the holes for the CTS pot shafts.

Probably using a drill press and a stack of them with a template to drill through on top?

Leave it there, I very seldom look under the hood of my RICS mind you.

[teb]

It's a shock absorber. You have two things going on here. First of all, Plexiglas and other brands of acrylic sheet material will tolerate a certain amount of screwed-on fitting pressure. As soon as you go past that amount, it shatters. The tape provides a little bit of cushion, so you can snug the fitting enough that it won't move, but not over-stress the plastic (but don't push your luck when tightening fittings). The other factor which contributes to the vulnerability of these materials is that machining them (sawing, drilling, sanding edges, etc.) builds up internal stress inside the sheets. These stresses stay in the material and tend to make it even more prone to shattering. Interestingly, the application of solvents to the machined piece can also cause it to shatter - often in a series of small cracks radiating outward from something like a drilled screw hole. This means that you also need to be somewhat careful about the application of solvents, solvent-based paint, cleaners, etc. on machined acrylic.

It is possible to reduce the stress after machining, though it is most likely not something being done on factory-built parts. What you do is to machine the piece and then anneal it. When I make my guards I stick them on a flat cookie sheet and put them in the oven at about 200 degrees for about an hour. Then I turn off the oven, leave them in there and don't open the door until it has cooled back down. At this point, they are still plexi and still fragile, but the internal stress level from machining is greatly reduced and not making them even more fragile. I learned this technique from guys making replacement taillights and similar parts for classic cars. I bevel and polish the edges of the guards I make for my guitars (looks a heck of a lot better than a cut and quickly sanded edge) so they get a lot of machining through the process and always get annealed before painting.

If you really need to remove the old tape residue, you will probably need to use some sort of solvent. I might be inclined to try Goo Gone or another citrus-based product, though I don't know what effect it may have on the paint and I would avoid getting it down into the holes (machined edges). I would rather replace the tape with new tape, right over the old residue and be done with it.

[maxwell]

^^^ Good info. Thanks.

[PunchyStrummer]

How do I create the holes for the shafts if I were to put on new masking tape?

[teb]

The holes in the tape? I just go to the back side of the guard, stick the tape over the holes and then use something like a small, sharp hobby knife to open up the holes.

If you're working on guards and making holes in the plastic itself, you need to be aware of the fact that acrylic has a very nasty habit of cracking just as the drill bit is exiting through the material. Drilling through tape is not likely to prevent this cracking. They make special drill bits for Plexiglass that are designed to prevent this (most of the time). The other option is to get a small, pointed file bit for a Dremel tool and essentially grind starter holes in the material, rather than drilling them. Once you have filed a small hole all the way through you can usually then use a regular drill bit to enlarge the hole, countersink it for screw heads, etc. as needed without shattering the area around the hole.

[PunchyStrummer]

Thanks for the info.

I decided to try putting double sided tape between the tape and the residue to preserve the original look - seems to work pretty well.

[jps]

Are you saying that you are putting the original tape back in place using the double sided tape to hold it in place? Great idea.

[PunchyStrummer]

Yes, now it looks basically like it was before (besides the edges being slightly raised, but not heaps).

[jps]

Cool. Keeping these looking original is always a good thing.