Bondo for holes?

[lindak]

Using MDS (I think it is, high end plywood looking stuff, smooth surface both sides, pricy)
with small cut outs of some kind of board...composed of sawdust, very flat, smooth, not as pricy...that I've gorilla-glued to it's surface....
and screwed in, counter sinking the screws.

It's for outside. It will be very well painted.
Will Bondo hold up as a filler in these holes?
Any thoughts?
thanks..Linda

[stickman]

Linda,

Bondo works well, doesn't shrink. What are you using these material for?

[lindak]

Hi, Jay...
It's for a sign that will be brought in from the street when a shop closes...brought back out in the morning with the day's specials.
I never used bondo before...nasty but great....
I'm used to something called EpoxySculpt, if I remember the name right, it's not right here, no fiberglass content...
I was told Bondo would be best.
Well, humidity kept rising....
and the last stuff I applied set up, but is still sticky.
I'm a bit concerned, but think it's just the humidity.
It's not like the mixing instructions are hard edge...
trying to measure 3 tablespoons of the stuff to 1quarter teaspoon, or whatever it was...
is fine to say...
but, that stuff is nasty.
If I had known it would be sticky, I would have used more hardener...
It will lose the stickiness, right?
Linda

[terryd]

Linda,
We use bondo in all our paint grade products exclusively and its great especially the fact that it doesnt shrink and dries quickly even under water. Tried "plastic wood" once and it was pathetic by comparison. If you mixed it in the right ratios then that sticky feeling is more a "rubbery" feeling. During curing the amount of internal heat generated can cause a substance to "boil" out and this is what remains. Sanding this "rubber" off usually reveals a hard smooth and dried surface. We usually mix by colour. Light pink means a slower set and umber means you have about as long to get the stuff in place as you can hold your breath..... Hope this helps... We use about two gallons per month and that "sticky" if is really "rubbery" is "normal" BTW a blob of Bondo about the size of a tea cup can cause enough heat during curing to be painful to the touch...

Terry

[lindak]

Well, I turned the air conditioner on in the shop in hopes of giving the Bondo some drier air to unstickify itself in....
It was only this morning I got your post, Terry...
So, after this coffee kicks in,
I'll go sand down what I did yesterday, and see what results.
Interesting info about the "sticky"="normal"...
that was sure good to hear.
.....Terry, your paint sounds interesting to me...
with what I get into, can you tell me more?
Linda

[kfitz]

Durham's Water Putty works great too. Not nasty, and easy cleanup. Also, it actually expands slightly as it cures. http://www.waterputty.com/

[kfitz]

Oh, BTW, sounds like you are using MDO (medium density overlay) plywood for you base material. It is great stuff to work with, and the water putty will work well with it.

[lindak]

Terry, you were right on the nose with the "rubbery" description.
This morning, that "rubbery" surface sanded right off and I was able to get a beautiful surface that nicely rounded and blended into the carved up areas.
It's still not my favorite stuff to work with,
but, I'm quite impressed with the results.
Getting more Bondo tomorrow for projects yet to be.
Thanks, guys, for the info.
Yeh, Kevin...it's MDO I was using...
but, I've no idea what this compressed sawdust board is...really like it though.

[stickman]

I usually buy a quart can of Bondo. We used to buy gallon cans, they would start to crystalize from opening and closing the can frequently. I am only on my second can of Bondo in three years. I have even used it on some finished projects, like oak drawer fronts, when a hole got drilled in the wrong spot, lucky enough it would be hidden by hardware.

I have even used Bondo to fill a mistake hole, then remachine the opening. It does machine great. My youngest brother has tryed to get me to mix a can up completely.. vibrate it to reduce the air holes and machine it, but I haven't come up with a project yet to do such a thing. Unless I was to make fishing weight molds or something, like that.

Anyhow, I love having it in my arsenel. Except for the fact the first time I used it, I was in the habit of slinging sheetrock mud, Bondo has a tendency to fly everywhere!!

Jay

[terryd]

Jay,

If you do mix the whole can then do it outside preferably during the coldest day of the year... she will smoke ;-)... Great stuff for creating extremeties on prototypes eg.. ears on a dog or appliques. Create the basic outline with ball of chicken wire and cover with bondo. Use the cheese grater to shape before it gets completely hard and sand to finish when completely cured...Modeling clay for adults.

Terry

[imacarver]

Bondo is not always the most effective product for filling. Since wood has to expand/contract and Bondo does not, the wood will seperate from the Bondo and you are left with a crack around a solid piece of Bondo.

[joe]

Jay & Mike,

Here's a little technique we've used for years to patch up, or mend holes and splits.

Mix half and half bondo and epoxy resin. This makes a pourable, molasses like, solution. Mix in the hardners just before the pour. This will seep into the smallest cracks and provide a glue like machineable surface.

I really like this technique.

Keep up the good work.

J.
www.normansignco.com (http://www.normansignco.com)