Bondo strength

[pjoseph]

I plan on using some bondo to fill in any imperfections around the cut-out of my sub box to make it flush.
is there a chance that bondo will crack in the future? If yes is there something else I can use.
Also is there like a minimum thickness that bondo has to be applied in order to keep it from cracking?

thanks

 

[highfigh]

If you're just filling gaps in a hole that's not perfect and will be under pressure fron the edge of the woofer, I would use polyester resin. This is the same stuff used with fiberglass and will soak into the MDF, particle board and will grab onto wood or plywood better than Bondo, although Bondo grabs pretty well. Thin is best but if the filler in the gaps won't be subjected to any major stresses other than vibration, it should be fine.

You need to wear a good respirator when you sand either of these, or when sanding MDF, plywood or any other wood products.

 

[lsiberian]

If you're just filling gaps in a hole that's not perfect and will be under pressure fron the edge of the woofer, I would use polyester resin. This is the same stuff used with fiberglass and will soak into the MDF, particle board and will grab onto wood or plywood better than Bondo, although Bondo grabs pretty well. Thin is best but if the filler in the gaps won't be subjected to any major stresses other than vibration, it should be fine.

You need to wear a good respirator when you sand either of these, or when sanding MDF, plywood or any other wood products.

I will add that if you have an orbital sander most can be hooked up to a shop vac and do an amazing job of sucking up the dust. Dust collection can't be overrated IMO. It makes life much easier. And if it's good enough a respirator may not be necessary. However it's always better to protect your lungs. With my sander I never see dust.

 

[MidnightSensi]

If you use resin you'll need to add a filler/micro-baloons. Resin itself is just a binder.

If your worried about toxicity, then just use epoxy rather than vinylester.

A mask should be worn if you use microbaloons (they are like a really fine dust and they will fly up and get into your lungs), but, other than that I never use any protection. You for sure don't need a respirator, not even OSHA would make you do that.

You can pick all this stuff up at a marine supply store.

 

[lsiberian]

I plan on using some bondo to fill in any imperfections around the cut-out of my sub box to make it flush.
is there a chance that bondo will crack in the future? If yes is there something else I can use.
Also is there like a minimum thickness that bondo has to be applied in order to keep it from cracking?

thanks

I think it will be fine. Bondo is used on cars for crying out loud. If it can withstand those forces it can withstand your subs vibrations.

I doubt it cracks anytime soon, but few things will last forever. It will probably last as long as the paint job.

If you used titebond your joints are probably sealed. Especially if you use it like I do. If you are worried. I suggest you squeze some more titebond into the cracks. It was by far the best glue. in Torsion machine testing done for an article in woodworking magazine.

 

[highfigh]

I will add that if you have an orbital sander most can be hooked up to a shop vac and do an amazing job of sucking up the dust. Dust collection can't be overrated IMO. It makes life much easier. And if it's good enough a respirator may not be necessary. However it's always better to protect your lungs. With my sander I never see dust.

I have a Porter Cable sander with the little useless black filter that fits onto a round tube. I got tired of dealing with it so I checked into the Porter Cable accessories and found that they have a hose that connects to a Shop Vac, for the low, low price of $30, which I think is insane. I went to Home Depot and in the aisle with washing machine hoses that hang over the edge of a tub, the light gray one with the plastic part that maintains the curve was $9 and it fits the sander perfectly. The best part is that the rubber end fits the small hose of a Shop Vac perfectly, too.

 

[jamie2112]

Bondo will be fine if you are sanding and painting. Resin is a freakin mess to deal with....just my 2 cents worth.....

 

[highfigh]

Bondo will be fine if you are sanding and painting. Resin is a freakin mess to deal with....just my 2 cents worth.....

It's a mess but for sealing all of the surfaces of a box, it works really well because it soaks in. I use cheap bristle brushes for that and if I have a bigger object to coat, I use a small, low nap roller.