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Posted (edited)

I thought about and made up a jig for rotating a guitar while you spray it. It can be rotated to any angle for convenience.

The jig is simple with 2 brackets that can be screwed to a table and a headstock mount which is 1/4" rod and uses two tapered bushes that fit through a tuner hole. They are locked in place by a nut and washer on each side. The body end has a 3/16 rod with about 1" turned down to 1/8". A fractionally smaller hole is drilled in the tail pin location and the rod tapped home. To remove it just clamp a pair of vice grips on and pull it out. The vice grips are used to turn it as well.

I used it when I sprayed my semi-hollow body guitar today and it worked a treat. For masking and sanding work it is excellent as well.

I found spraying in the flat position you could put a nice wet coat on without runs although I did manage that on the peg head so will sand back and redo that piece. For the curious the body is mahogany and chambered and has a curved profile block added to the centre block front and back with a 1/8" maple skin glued front and back. You cant tell from the pictures but it looks just like a arch top.

2006_1029Image0063.jpg

http://i54.photobucket.com/albums/g111/One...29Image0064.jpg

Edited by Acousticraft
Posted (edited)

This is the skeleton underneath the front and back. The profile block that glues to the center block gives the body its arch in both planes. The body is heavier than a normal ES335 but Im hoping it may be more acoustic with solid maple front and back. The ring to clamp down the skins is pictured as well. I use plastic cling wrap under the ring so any glue sqeezed out will stick. I used double sided tape to stick the clamping ring to the skin so It didnt move as I lined every thing up for gluing.

OCT2006059.jpg

Edited by Acousticraft
Posted (edited)

Cool idea!

You can put a LOT thicker coats when the guitar is not hanging from the ceiling. I guess it would speed up the finishing process somewhat.

Looks a bit flimsy though. I wouldn't probably have the guts to put the result of my efforts hanging on a pair of pins.

But I guess that's just a prototype. (the jig, I mean) :D Also, what is that huge white line near the bottom pin? Looks like one huge scratch!

What if you're strap button aren't in the traditional spot? Can you lock it into place somehow?

Edited by Jester
Posted

There is no problem strength wise unless you want to do some heavy work but for light sanding between coats and masking it is ideal. The line showing is where I had to fill it but it is now a blood red colour all over so can't be seen. The timber I used for the body was made from 4 pieces glued together and was not as good as I hoped, it had a few flaws which werent obvious until it had been machined. I dont like to waste timber so planned a colour finish to cover flaws.

After watching the ES335 Eric Clapton video the guy paints the guitar hanging from the body end. They must have an eye bolt that screws in the tail pin hole to hang it from.

Hey Mike a nice tidy workshop. Looks clinical unlike my car shed.

Posted

That's a nice build idea, can you give more details on the top thickness and how you managed to get it glued down? Did you use heat or wet the board? I imagine it would give a fight and try to pop up afterwards ? -Thanks -Vinny

Posted

That's a nice build idea, can you give more details on the top thickness and how you managed to get it glued down? Did you use heat or wet the board? I imagine it would give a fight and try to pop up afterwards ? -Thanks -Vinny

Vinny- At 1/8" it would be similar to an acoustic top or back, and the radius is held with very light bracing and shaping the rim. No heat is applied, and most definately no water. I would think it would hold just fine as his guitar has a lot more glueing surface than you have on an acoustic, and this one won't virbrate like an acoustic.

Acousticraft- The guitar is looking nice, and that is a smart little jig. Simple and effective :D .

Peace,Rich

Posted (edited)

I have lost this reply twice from bumping the wrong key on my lap top so I'm a bit annoyed.

The jig works well and I will put my last clear coats on tomorrow hopefully.

The top and back have no bracing as the double curvature makes them stiff even the front with the "F" hole. They are 3/8" thicker than the sides are at 1 3/4".

The skins were glued down by firstly clamping the center block area with a strip of plywood so it would bend to the profile block shape and this stops the seam opening up. Then I used the clamping ring in the picture and clamped the edges with about 12 clamps. It is neat to see the arch forming as you pull the skin down.

As this is a prototype I will look at reducing weight in the body by narrowing the rim width and the center block behind the tail piece and maybe even drilling holes in the center block. I don't know what the sonic implications of joining both chambers are? Maybe feed back?

Edited by Acousticraft
Posted

I have lost this reply twice from bumping the wrong key on my lap top so I'm a bit annoyed.

The jig works well and I will put my last clear coats on tomorrow hopefully.

The top and back have no bracing as the double curvature makes them stiff even the front with the "F" hole. They are 3/8" thicker than the sides are at 1 3/4".

The skins were glued down by firstly clamping the center block area with a strip of plywood so it would bend to the profile block shape and this stops the seam opening up. Then I used the clamping ring in the picture and clamped the edges with about 12 clamps. It is neat to see the arch forming as you pull the skin down.

As this is a prototype I will look at reducing weight in the body by narrowing the rim width and the center block behind the tail piece and maybe even drilling holes in the center block. I don't know what the sonic implications of joining both chambers are? Maybe feed back?

Your center block and sides are effectively heavy bracing(more stucture than an acoustics light bracing *that is what my comparison was based on). The only spot that looks like it could give you trouble don the road would be around the lower bout F hole with control knobs, but I am sure you did something to re-inforce that area(maybe a bit of backing). Seems like you took extra care in clamping the top evenly. Very nice planning :D .

Just a thought... Why not take your sides a step further and bend and kerf them? It would be much less material(you could rip a stack of mahogany sides for next to nothing). It would also give you 100% side grain with instead of some end grain. Just a thought, take a peek at Mykas in progress topic-Myka's 335-ish.

Can't wait to see some finish pics. I think it is looking really nice. Great job!

Peace,Rich

Posted (edited)

The idea was to be able to make a semi-hollow quickly without the time and effort required for making molds, jigs and kerfed linings etc.

Even a true semi-hollow does not have great unplugged acoustic volume because the strings are not vibrating over a sound hole, the center block locks the top down which prevents vibration, so are in reality mostly cosmetic. I played a brand new Gibson ES335 and was disappointed at its acoustic volume, not much different than a good solid body.

The top didn't need reinforcing (I did think about reinforcement around the "F" holes) and that would have made it more difficult to clamp it down, and may have caused problems with getting nice curves. I think if you went thinner than 1/8" then it may not be stiff enough.

I just finished the clear coats on my Axe and I am definitely improving with my lacquer finishes. You definitely need a wet coat so it will flow out smoothly. In the past I have sprayed my coats too thin and it ends up orange peely. The ability to rotate and lay the guitar flat and shoot a nice wet coat is awesome.

I have been using a small 2hp compressor with a basic suction gun. In the past I have set the regulator on the compressor and run a 30 ft hose to the gun but this time I plugged in a regulator / water trap at the gun so full pressure is in the line. This gives slightly more air volume and means there is not the same pressure drop running thru a long line with an underpowered compressor. I sprayed my lacquer at 20 PSI and found it minimized over spray and reduced air consumption and still got a nice finish. I ended up using 1 1/2 liters lacquer and about 1/4 liter sanding sealer.

The Miro tone brand Micro cat 1220 lacquer is an awesome product to apply.

I have 1500 grit to wet sand after a week. Is this a suitable grit or too coarse?

Edited by Acousticraft

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