epoxy resin vs polyester resin sealing inside subwoofer box

[akadj 10+ year member]

I'm just wondering what is people's preference when it comes to sealing up your box?

epoxy...635 thin or150 thick?

poly...404 tooling or 435 standard

or maybe you have used something else?

Click to read more...

 

[mlstrass 5,000+ posts]

caulk to seal seams, but tight glue joints don't even need that...

 

[ciaonzo 5,000+ posts]

You talking a coating/lining of all interior walls?

 

[Durango03 10+ year member]

lol, Im going a bit overboard with my build, but Im using liquid nails, course thread drywall screw, caulk, bondo (all in seams and joints), and 404 resin covering entire inside with mat covering seams and joints

 

[akadj 10+ year member]

caulk to seal seams, but tight glue joints don't even need that...

not what I mean...

You talking a coating/lining of all interior walls?

exactly!

 

[akadj 10+ year member]

lol, Im going a bit overboard with my build, but Im using liquid nails, course thread drywall screw, caulk, bondo (all in seams and joints), and 404 resin covering entire inside with mat covering seams and joints

so you added mat with 404 resin, with just 404 do you think if it flexs the resin will break or crack as 404 is the most brittle no?

have you already built this or still under construction?

 

[Durango03 10+ year member]

Still under construction. there is a build log on here. But no I dont believe it will crack. the enclosure will be ridiculously sturdy with the other compounds as well as the 2x3 bracing Im going to be throwing in there.. it wont see much (if any) flex to allow cracking.. Also from other threads I have read, adding resin to the inside is always a good idea to contain the air that escapes (while the use of resin is debatable as far as usefulness goes). The one thread that sticks out in my mind, the OP advised everyone to place a vacuum hose on a piece of MDF and feel the air being ****** out on the opposite side.. resin will prevent the issue.

 

[mlstrass 5,000+ posts]

liquid nails ***** ***, use wood glue on wood. Crazy concept I know...

All the other crap you're doing is not needed, but if you feel inclined then have at it.

FG resin/mat does nothing to make a box stronger unless you lay it on 1/4" thick. Single layer is a waste of time and $$$...

As for that video, not buying into that. Static electricity perhaps. Light a candle, put a big piece of MDF in front of it, now hit the MDF with 125psi from an air compressor. Tell me if the candle blows out...

 

[xtremekustomz 10+ year member]

I shot this video using our cnc router the other day at work. I never though mdf was this porous but the video kinda proves that it is.

video0003 - YouTube

 

[ramos 5,000+ posts]

Polyester if you want to seal it. All you're doing is sealing it.

 

[ciaonzo 5,000+ posts]

liquid nails ***** ***, use wood glue on wood. Crazy concept I know...
All the other crap you're doing is not needed, but if you feel inclined then have at it.

FG resin/mat does nothing to make a box stronger unless you lay it on 1/4" thick. Single layer is a waste of time and $$$...

As for that video, not buying into that. Static electricity perhaps. Light a candle, put a big piece of MDF in front of it, now hit the MDF with 125psi from an air compressor. Tell me if the candle blows out...

There is a huge gain in strength when you turn anything into a monocoque-like structure.
Also, have you ever tried breathing very fast or hard through certain fabrics or whatever and had a tough time, but when you breath easy and slow through it there's no problem? That's the concept behind aperiodic membranes, they become more resistive to higher velocities. MDF is porous, period. There are losses built into modeling programs that acknowledge facts like these.

 

[keep_hope_alive Premium Member]

i agree you want to coat the interior of the enclosure - polyester resin is sufficient, a few layers of glass at the corners can't hurt.

 

[akadj 10+ year member]

i agree you want to coat the interior of the enclosure - polyester resin is sufficient, a few layers of glass at the corners can't hurt.

I agree and I know that adding a 1/4 layer of resin is a MUCH harder surface then say adding the same amount of wood. which is why it helps gain spl. I've even seen a box made entirely out of glass and some lined on the Inside with tile.. hmm maybe I should try tile?...

but.. as for resin type.. epoxy is not the same as poly.. poly is less then half the price and the chemicals require you to wear a mask and gloves.. not the same with epoxy.

 

[akadj 10+ year member]

probably should have used the word "density" .. lol

 

[momax_powers 10+ year member]

As far as mdf being porous and having air pass through it... Couldnt a couple layers of primer solve that?