First build, in progress...

[captainobvious99]

Re: First build, in progress...

[QUOTE=gowa;1631196]

Disaster strikes ! :eek:

Well, I did say Id post my failures as well :o

BUMMER! Inspected the work after setting overnight...Looks like there was a bad reaction with the foam. I dont know if resin seeped through the painters tape in sections, or if the colder weather played a role, but its lumpy... Not good. Looks like this one may be a scratch. Didnt even cure all the way yet because of the cold air. I could probably salvage these to make one shell with alot more elbow grease, but It wouldnt make a great mold at this point, so Im probably going to scrap it.
Thinking about it, it may not be such a terrible thing...The enclosure volume wasnt going to add up to the result I wanted anyway. It would have required a higher tuning with just 60L or so of estimated volume, OR it would have had to have been a sealed enclosure. At least now I can plan it out a bit better on the mulligan.

I'm seriously considering just doing a wood enclosure now. Curved back utilizing either bent ply construction or kerf. Rounded back using these techniques will still give a not so boxy look, but they will end up still having the flat tops...decisions decisions...


Pics, of course below



Put it on Ebay and sell it as art.

People WILL buy anything... :rolleyes:

[gowa]

Re: First build, in progress...

[QUOTE=captainobvious99;1630920]Disaster strikes ! :eek:

Well, I did say Id post my failures as well :o

BUMMER! Inspected the work after setting overnight...Looks like there was a bad reaction with the foam. I dont know if resin seeped through the painters tape in sections, or if the colder weather played a role, but its lumpy... Not good. Looks like this one may be a scratch. Didnt even cure all the way yet because of the cold air. I could probably salvage these to make one shell with alot more elbow grease, but It wouldnt make a great mold at this point, so Im probably going to scrap it.
Thinking about it, it may not be such a terrible thing...The enclosure volume wasnt going to add up to the result I wanted anyway. It would have required a higher tuning with just 60L or so of estimated volume, OR it would have had to have been a sealed enclosure. At least now I can plan it out a bit better on the mulligan.

I'm seriously considering just doing a wood enclosure now. Curved back utilizing either bent ply construction or kerf. Rounded back using these techniques will still give a not so boxy look, but they will end up still having the flat tops...decisions decisions...


Pics, of course below



Put it on Ebay and sell it as art.

[captainobvious99]

Re: First build, in progress...

Just noodling around in Sketchup. Pretty cool program, albeit a bit difficult to get curves and rounded edges done well.

Heres a quick example of a design I muddled up.

[davepellegrene]

Re: First build, in progress...

They don't look that bad in the pics. I would think you could salvage the molds. Could you cut a 1/4" piece of plywood and set it in the center oval to make it flat again. Then skim the whole box out with bondo or easier yet stasmooth 45 set. Home Depot carries stasmooth for about $7 a bag. It sands nice and easy and won't shrink or crack. It would even fill in the oval part if you wanted to do several coats. Its in the drywall section. Then paint over that to seal it up.

The cold can make resin not set at all. I have had it ruin a gallon by leaving in my garage all winter. It likes 70 degrees. Hotter it sets faster. Colder it may not set at all.


Dave

[djg]

Re: First build, in progress...

Tan polyurethane foam does not react to polyester resin. Styrofoam does. Epoxy works well with styrofoam.

[evilskillit]

Re: First build, in progress...

Thats the spirit. Don't give up. Keep up the good work and keep posting plenty of pics.

[captainobvious99]

Re: First build, in progress...

Thats a real bummer. I only ruined 2 baffles a few days ago and that hacked me off royally. I can't imagine spending a few days or weeks making an enclosure mold and having it go sour on the last step. Sorry to see things go that way. Good luck with whatever you do. I'm sure it'll be cool no matter what.

Thanks for the support

Im back to the drawing board for the enclosure design now. I'll hopefully have something drawn up in a couple days.

[evilskillit]

Re: First build, in progress...

Thats a real bummer. I only ruined 2 baffles a few days ago and that hacked me off royally. I can't imagine spending a few days or weeks making an enclosure mold and having it go sour on the last step. Sorry to see things go that way. Good luck with whatever you do. I'm sure it'll be cool no matter what.

[captainobvious99]

Re: First build, in progress...

Good tip, thanks!

[PhyrraM]

Re: First build, in progress...

If it is indeed resin reacting to ("melting") the foam, then a good coat of latex paint before (or instead of) the tape or foil should do a good job of sealing the foam 100% from any outside material. That's what some of the car guys do for custom fiberglass body panels.

I believe they use a waterbased latex paint because it doesn't react with the foam OR the resin. It likely adds a few more days to a build in cold weather because it can take a while to completely dry/cure.

[captainobvious99]

Re: First build, in progress...

What a shame! That was a beautiful form.:(

I'd love to see that finished! Free-hand shaping is a remarkable talent, looks like you had it spot on.

I think the concept is valid, just lacked proper execution. Try again using proper materials. I'd love to see that completed!

Yeah, I went based off my previous experience using the painters tape and polyester resin and it has always worked very well. The things I didnt consider were:

1- The colder weather making curing more difficult
2- The reaction of the foam to temperature
3- What differences might be observed when using the Vinyl Ester resin

Live and learn ! :o

What I probably should have done was lay down a layer of aluminum foil before the fabric strecth. I dont think I would have had any issues at that point.

I need to pull the "work" off of the mold this evening and see what it looks like. Then I'll know from there if its salvageable or not. I kind of doubt it though. I know I can make this method work...its just a matter of executing it better, as you said.

[robwest]

Re: First build, in progress...

What a shame! That was a beautiful form.:(

I'd love to see that finished! Free-hand shaping is a remarkable talent, looks like you had it spot on.

I think the concept is valid, just lacked proper execution. Try again using proper materials. I'd love to see that completed!

[captainobvious99]

Re: First build, in progress...

Disaster strikes ! :eek:

Well, I did say Id post my failures as well :o

BUMMER! Inspected the work after setting overnight...Looks like there was a bad reaction with the foam. I dont know if resin seeped through the painters tape in sections, or if the colder weather played a role, but its lumpy... Not good. Looks like this one may be a scratch. Didnt even cure all the way yet because of the cold air. I could probably salvage these to make one shell with alot more elbow grease, but It wouldnt make a great mold at this point, so Im probably going to scrap it.
Thinking about it, it may not be such a terrible thing...The enclosure volume wasnt going to add up to the result I wanted anyway. It would have required a higher tuning with just 60L or so of estimated volume, OR it would have had to have been a sealed enclosure. At least now I can plan it out a bit better on the mulligan.

I'm seriously considering just doing a wood enclosure now. Curved back utilizing either bent ply construction or kerf. Rounded back using these techniques will still give a not so boxy look, but they will end up still having the flat tops...decisions decisions...


Pics, of course below

[captainobvious99]

Re: First build, in progress...

Applying painters tape




Fabric stretching. Yup, almost the same color as the painters tape...purely coincidence. Picked it cause the color shows flaws well







And in my walkout from the basement awaiting glassing. I figured since theres a doorway between here and my basement, and the walkup leads to fresh air, I shouldnt be smelling fumes in the house. Of course I was wrong :(

[captainobvious99]

Re: First build, in progress...

Thinking about enclosure volume now...

Assuming I dont try to fiddle with gaining extra enclosure volume by utilizing the stand as additional airspace (this probably wouldnt work well anyway), I am looking at somewhere in the neighborhood of 60 liters of volume for the pair of 8955a woofers. Stuffing heavily might give slightly more wiggle room. I have a couple of choices- I can either -

1: Go vented with a smaller airspace, and tune 60L, 30hz
2: Go sealed with a 60L airspace, Qtc 0.61
3: Go sealed with a 40L airspace (add mass), Qtc 0.71
4: Switch to Dayton RS225-8 drivers (sealed, 61.2L - 0.71 Qtc)

Recommendations?

Im not opposed to adding a sub for low end if needed, but I'd obviously prefer to avoid it if I can.