Acrylic Fabrication Q & A

[dbl]

Two possible things going on here - way too much solvent, and not enough pins.

I squeeze the solvent bottle before I apply. this give me more control over how much comes out.

I also use pins every 6". and I blow out the seam with air before apply the solvent.

I'm thinking I simply used way too much solvent. I did squeeze the air out of the bottle before starting. I had the pins about every 4-5 inches. I didn't blow out the seam...forgot about that one!

Thanks so much for the help. I think you've talked me off the ledge enough to give it another try. Like I said, I don't give up easily so this was pretty frustrating. Thanks again!!!

 

[Turbo's Aquatics]

A couple more things:

1) only remove the paper at the bonding surface. The front panel paper should be left on the bottom, where you had the foam stick to the panel. The paper will protect the acrylic from solvent

2) no overage = no fillet on outer edge = solvent will run down the routed edge = solvent leaves joint = air intrudes = too many = signs. Sorry for crazy with = there whew!

You're getting really close though, just the overage would probably avoid the foam/binding thing because the solvent would not run out

Also leaving paper on the face means that when you go to flush trim off the overage lip, you won't have any bare acrylic sliding across the table or in contact with a router base. That bare acrylic will scratch up, or the edge of the paper (which is tacky) will snag and turn the assembly or roll up and jam

 

[cromag27]

Yeah use less solvent and once you pull the pins , you can use light downward pressure on the panel for a couple minutes. but you have to be careful to keep the panel at a 90 angle.

 

[cromag27]

Duh, I just noticed you didn't have overage!

 

[dbl]

I thought the overage was just on the top and bottom panels. Those two panels are cut a little larger for overage. So maybe this is where I screwed the pooch.

So if I have overage on the front panel, I would have to flush trim it before affixing it to the bottom/top? Is that correct? Maybe I need to go back and re-read from the beginning...lol.

 

[cromag27]

I save all my flush cutting for the very end.

 

[imustbenuts]

Curious what you cleaned the acrylic with before bonding?

 

[dbl]

If you're asking me, I used a slightly damp cloth and dried it well with a lint-free cloth.

 

[imustbenuts]

If you're asking me, I used a slightly damp cloth and dried it well with a lint-free cloth.

Yes, i was asking you, sorry. I used denatured alcohol, 1/2" over cut front and back panel length wise, can probably get away with 1/4" but I wanted more to press on when inserting pins, and blew the seam out with can air once the pins were set. I liked using a 25 gauge applicator needle instead of 22 guage. The solvent seemed more controllable to me. This technique was very successful for me.

 

[Lowell Lemon]

That web actually belongs to the one who does exclusive capillary. He is responsible of causing damages worth thousands of $ or may be more to hobbyists worldwide. I don't know about the calculator though![/QUOTE

The calculator is the same as the one by Cyro Acrylics it seems to be correct.

I agree with your spotting bonded seams with saw marks and not prepped for the best bonds. Good catch.

 

[Lowell Lemon]

@Floyd R Turbo @Lowell Lemon when I was looking at thickness calculators on-line, I kept seeing for water vessels to use 2 part. Solvent shouldn't be used. What say you?

I have experience with two part and use it on some builds. Those builds demand two part due to the difficulty of using solvent methods. An example would be a large Hexagon tank with the multiple 15 degree cuts and resulting 30 degree bonds for each corner. You need a thickend bonding material to avoid the solvent running out of the bond when the parts are end to end in a 30 degree jig. The rest of the bonds would be solvent for the top and bottom making a very strong structure that does not depend on the corner seams for strength.

The plastics engineer that helped me overcome manufacturing problems recommended the solvent method in most cases. The two part is only a tool in my bag of tricks but not the preferred tool based on experience and results. Most people are unwilling to invest in the equipment necessary to use two part like a mixing gun and the use of Weldon 42 in the 250ml tubes but it provides the best control in hard to control solvent bond locations. Weldon 42 has a shelf life and is affected by heat so you have to buy a case and use it up in a short period. That is another reason I avoid using it.

 

[Lowell Lemon]

@dbl ,
When I looked at the pictures of the parts to be joined I noticed you have very little excess acrylic on the outside of the seam area. What I mean is this. You should leave about a 1/16" excess material to prevent the solvent from running over the side of the part into the foam underneath the parts. After the parts are set up the seam is trimmed back with a flush trimming router bit (0ne with a bearing on the end of the flutes). So in practice the face panel should be about 1/8" larger in length than you finished length. Example finished length 12" on the face but the part before trimming is 12 1/8" at the time of bonding. Hope that makes sense to you. You need an area to capture the expressed solvent and prevent it from simply flowing over the end of the part and onto the foam tape.

This is part of the art of acrylic bonding. So oversize the face and back parts and trim back to flush after the bond. If you try this I think you will have better success. You are on the right track. Weldon #4 is not as aggressive as the solvent mix described on this thread and as such will not bond as fast or strong. It will be fine for your purposes. Give it another try. You can do it!

Sorry I did not see that Floyd R Turbo already made the catch on the fillet seam needs.

 

[dbl]

Thanks...I truly appreciate you guys for helping out. I really didn't expect it but I will give it another shot with the tips from this evening. As I said earlier, the bottom and top are oversized...I just didn't do it for these panels.

Live and learn...thanks again to all.

 

[cromag27]

The good news is you have a wealth of knowledge right here. I first started working with plastics over 10 years ago but it took me quite some time before I was decent at it. I didn't know about the mega thread on the other forum and I went through a lot of trial and error. And while I can do displays, I'm still learning new tricks to make my life easier. at this point I'd say you're still well ahead of the learning curve I went through.

Thanks...I truly appreciate you guys for helping out. I really didn't expect it but I will give it another shot with the tips from this evening. As I said earlier, the bottom and top are oversized...I just didn't do it for these panels.

Live and learn...thanks again to all.

 

[TherealplexiG]

@cromag08
I have literally blown up more then couple of thousand, just to get a hang of it. I'm not saying it wasn't fun and interesting. But there are things in this art that no one can teach you and you have to experience them in-order to understand. It's like developing a gut feeling with in yourself to do proper things at right moments. James used to say this "If i could teach you this art of acrylic fabrication, i would make alot of money. But there are things which can not be explained, you have to experience in order to learn them". And now i surely do understand what he meant.

 

[TherealplexiG]

I just did a test using thick gauge wire and I had solvent run out.

How thick was that wire you used for the test?

 

[cromag27]

I want to say around 18ga.

 

[TherealplexiG]

how you guys sand the edges, what distance do ya'll leave. Is it just the routed edge?
I leave approx 1/4" from the edge from where welded to one side (for eg. end pane doing vertical seams, and front pane doing bottom seam)and then mask. sand the entire area and then use quixx to bling bling.

 

[Turbo's Aquatics]

I would say I shoot for about 1/4", really it's only on the edge where the panel is bonded that need sanding (the squish out) so on the other face (typically the front/back) I try to get the tape as close to that edge as I can, like 1/8" maybe.

 

[TherealplexiG]

I would say I shoot for about 1/4", really it's only on the edge where the panel is bonded that need sanding (the squish out) so on the other face (typically the front/back) I try to get the tape as close to that edge as I can, like 1/8" maybe.

That definitely would help..