Mini Vacuum Table

[John_H]

I built a little vacuum table for making pickup covers. I've been wanting to do this for years, and now I'm kicking myself for waiting so long.

The table is built out of MDF, and the frames are Masonite. A while back, I purchased a 4' x 8' x 1/16" sheet of black ABS from a local plastics supplier so I was ready to go when I got it together today. I heated the plastic in a 375* oven for around five minutes. I only had time to make a couple this evening, but it seems to work great.

I designed it for 9" x 9" blanks. I wanted a size that would draw well, but not waste a lot of material. This is my first attempt at this. I'm pretty stoked with my initial results.

[John_H]

I had time to experiment today. So far, this has been fun. I learned from my last session that I need to lay something directly underneath my frames when I put them in the oven. I had some thin cardboard with a shiny finish on one side. It worked out well.

The best technique that I came up with was to set my oven to 375. I put the frame in over the shiny cardboard. I let it get really hot. Five minutes or so is enough. The plastic is now sagging down and laying on the cardboard This next part needs to be done as fast as possible for the best results. I Remove the cardboard and frame from the oven together and put it on the counter, lift the frame from the cardboard, set it squarely down on the vacuum table, and then turn on the 5 HP shop vac. I got pretty good at it with the little practice I had.

One of the main reasons I've wanted to make my own covers is that I don't really like the choices available for P-90's, Especially dogears. They're just not very attractive.

I made two different forms. Round, and pointed ears. After shaping the ABS, the outside surface isn't perfectly smooth. I trimmed to size, and wet sanded the cover's with first 1,200, then 2000 grit. A few minutes sanding leveled them out nicely. I need to find a good polish for the plastic.

[jonson]

Looks like your near enough there John and goodun Bro. I don't bother with bolts and getting the frames that tight and just use small spring clamps but there's more ways to skinning a cat so go with it. If you have a heat gun then try heating the dull underside of the abs instead of using the oven and you will get a better finish on the top shiny side. A heat gun can also help to give the plastic a bit of a push once it has pulled down to get crisper corners allthough go careful as splits can occur. Also try to locate HIPs or high impact polystyrene as it is far better for vacuum forming. If you have a bench grinder or even a motor driven shaft available then a soft buffing wheel and hard wax block is the best poss way of polishing plastic it's done in seconds the same way guitars are polished by the big boys only on a smaller scale. Your doing good with all your budget work as you call it keep it going John.
Solar energy potting I liked that and not something I could do here without serious global warming. In the uk you would spend to much time getting them out with an ice pick most of the year..

[jack briggs]

I had time to experiment today. So far, this has been fun. I learned from my last session that I need to lay something directly underneath my frames when I put them in the oven. I had some thin cardboard with a shiny finish on one side. It worked out well.

The best technique that I came up with was to set my oven to 375. I put the frame in over the shiny cardboard. I let it get really hot. Five minutes or so is enough. The plastic is now sagging down and laying on the cardboard This next part needs to be done as fast as possible for the best results. I Remove the cardboard and frame from the oven together and put it on the counter, lift the frame from the cardboard, set it squarely down on the vacuum table, and then turn on the 5 HP shop vac. I got pretty good at it with the little practice I had.

One of the main reasons I've wanted to make my own covers is that I don't really like the choices available for P-90's, Especially dogears. They're just not very attractive.

I made two different forms. Round, and pointed ears. After shaping the ABS, the outside surface isn't perfectly smooth. I trimmed to size, and wet sanded the cover's with first 1,200, then 2000 grit. A few minutes sanding leveled them out nicely. I need to find a good polish for the plastic.

Nice, John!

This stuff works well:

[John_H]

...If you have a heat gun then try heating the dull underside of the abs instead of using the oven and you will get a better finish on the top shiny side. A heat gun can also help to give the plastic a bit of a push once it has pulled down to get crisper corners allthough go careful as splits can occur.

Thanks for the tips! My research for this was limited to a couple of video's, and short "how to" articles. I anticipated that a heat gun would help, but I haven't had the need yet. I think I might be able to work with a smaller piece of plastic, and I plan to build another table with a 6" X 6" format to try and make my material go further.

Also try to locate HIPs or high impact polystyrene as it is far better for vacuum forming.

I initially wanted to get some polystyrene, but I couldn't find any locally. The ABS was inexpensive so I figured it would be good for my first efforts. I like the way this is working out, so I'll be ordering some HIP soon.

If you have a bench grinder or even a motor driven shaft available then a soft buffing wheel and hard wax block is the best poss way of polishing plastic it's done in seconds the same way guitars are polished by the big boys only on a smaller scale.

Cool. I have a few options for machine polishing.

Solar energy potting I liked that and not something I could do here without serious global warming. In the uk you would spend to much time getting them out with an ice pick most of the year..

That's usually the way I do it in the summertime. I like it because I don't have to constantly monitor the process like I do with the double boiler. There's no lack of solar power here in the middle of the desert.

Nice, John!

This stuff works well:

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Thanks Jack! I'll check it out.

[John_H]

I found some plastic polish that I forgot I had. It's made for restoring headlights. I used it and a 4" soft buffing wheel in my drill. It worked quite well. I don't think I'll be buying dog ear cover's anymore.

It's hard to get a good picture of these things.

[Chris Turner]

In that first picture, it looks like there's a lot of waste.

Can you put more than one form on there?

[John_H]

In that first picture, it looks like there's a lot of waste.

Can you put more than one form on there?

You're right. I chose the size based on the size of plastic cut for shipping purposes. I'm going to make a frame for 6" X 6" blanks. I think they'll be large enough, and most sizes that you can buy will cut into modules that size without waste. I'm a total beginner at this stuff. I'll get it streamlined. Meanwhile everything's getting recycled.

[jonson]

By all means make your smaller box John but don't cut up too much plastic to start with. If you go too small you can end up with overstretched plastic and splits and find that your 1/16 sheet has gone down to 1/32 in the bottom edges. Strat covers and Vox single coils should be ok on that size but watch out on your soapbars and dog ears.
I just noticed your buck has no pole holes in it and it sometimes pays to drill these undersized to help with the pull down. Once you redrill after then the dots have gone.

[jason lollar]

Caswell plating has alot of buffing compounds and pads and wheels for different applications. Looking good! I have been fussing with the same thing too for some time in order to make easy one off custom covers. I bought a small 110V heating element for a small cookstove. It was hard to find one in 110 but it makes it alot more portable.
Smaller shops that can make thier own parts at least to some extent usually wind up way ahead of shops that only buy pre made parts- seen it over and over. Almost like playing guitar but having to have someone else tune it for you

[John_H]

By all means make your smaller box John but don't cut up too much plastic to start with. If you go too small you can end up with overstretched plastic and splits and find that your 1/16 sheet has gone down to 1/32 in the bottom edges. Strat covers and Vox single coils should be ok on that size but watch out on your soapbars and dog ears.
I just noticed your buck has no pole holes in it and it sometimes pays to drill these undersized to help with the pull down. Once you redrill after then the dots have gone.

After some thought, I realized it would be silly to make another box. Instead, I'll just make some different frames to accommodate smaller pieces of stock. I'll go down to an 8 x 8 most likely as the largest I'll use. That'll almost double my yield from a 4'x8' sheet of material. I've been putting thumb tacks in the bottom of the forms to hold them up a little to pull the sides in better, and that seems to work pretty well. Thanks Bro.

Caswell plating has alot of buffing compounds and pads and wheels for different applications. Looking good! I have been fussing with the same thing too for some time in order to make easy one off custom covers. I bought a small 110V heating element for a small cookstove. It was hard to find one in 110 but it makes it alot more portable.
Smaller shops that can make thier own parts at least to some extent usually wind up way ahead of shops that only buy pre made parts- seen it over and over. Almost like playing guitar but having to have someone else tune it for you

Thanks for the input. I'll check out Caswell. We have a local specialty hardware store that sells several different compounds. I'll see what they have tomorrow before I buy anything online. I picked up a big toaster oven from a thrift store that my frames will fit in. I haven't had time to try it yet, but it will hopefully get the operation out of the kitchen. I dig making my own parts when I can. A lot of the pre-made stuff just doesn't look right.

[jonson]

Like the thumbtack idea Bro that helps to pull it tight. I generally make the bucks taller and stick a piece of course felt underneath to allow the air to pull through but tacks is good. The bottoms of your covers look very clean so you have a way of trimming them. I find a small diameter dremel saw blade in a pillar drill set to height and just poking about an 1/8 inch through a thin fence and the cover set upside down on the table with scratch protection cuts them very clean.

[Beef Coon]

Thanks for sharing, looks great.

I know I've read somewhere on here about using a dental vacuum forming machine - like this one:
Dental Vacuum Forming Molding Machine Former Heat Steel Balls Lab Equipment P5 | eBay

[David Schwab]

Here's two, made a lot like John's, that would be useful for pickup covers:

6 x 6 Vacuum Former Forming Thermoform Plastic Forming Box Machine Table | eBay

12" x 12" Vacuum Former Forming Thermoform Plastic Forming Box Machine Table | eBay

[John_H]

Like the thumbtack idea Bro that helps to pull it tight. I generally make the bucks taller and stick a piece of course felt underneath to allow the air to pull through but tacks is good. The bottoms of your covers look very clean so you have a way of trimming them. I find a small diameter dremel saw blade in a pillar drill set to height and just poking about an 1/8 inch through a thin fence and the cover set upside down on the table with scratch protection cuts them very clean.

I learned quickly that making the buck a little bit taller helps a bunch. I can picture the jig that you describe. Is heat a problem? What RPM?

Thanks for sharing, looks great.

I know I've read somewhere on here about using a dental vacuum forming machine - like this one:
Dental Vacuum Forming Molding Machine Former Heat Steel Balls Lab Equipment P5 | eBay

Thanks Man! I'm not familiar with those, but they don't look usable to me.

Here's two, made a lot like John's, that would be useful for pickup covers:

6 x 6 Vacuum Former Forming Thermoform Plastic Forming Box Machine Table | eBay

12" x 12" Vacuum Former Forming Thermoform Plastic Forming Box Machine Table | eBay

Yep, They're not high tech. Those are built similar to what I saw on a DIY website.