sawdust and glue

[gord104]

ok looked around but cannot find an answer.....strange request...does anyone know what kind of glue would be good for gluing sawdust together??here is the catch though....I have tried some wood glues and they are not what I am looking for,the glue has to dry clear,the end product cannot be bendable I want the product coming out if possible as stiff as a board,sorry had to,any knowledge of this would be greatly appreciated.about the best way to describe it..if there are any one out there that knows this please share...
thanks:U and sanding end product

[wheelinround]

Try using a moulding clear resin instead of glue

[gord104]

ok I will try that as well thanks...more ideas if someone has em

[Woodwould]

Animal glue mixed with sawdust is an old recipe for filling rot in furniture legs etc. It sets rock hard after a few days.

Any surplus can be moulded into very convincing looking dog turds and placed in strategic positions to cause all manner of alarm and hilarity.

[Master Splinter]

Epoxy and sawdust, if you get the clear sort of epoxy.

[Anodyne]

I have patched small holes while turning with cyanoacrylate and sawdust, try the thicker "gap filling"

[nearnexus]

When I did woodwork at school (many years ago) we were taught to use a mix of fine sawdust and Aquadhere wood glue to fill knot holes etc. Worked OK, but was quite visible as a filled in knot hole :).

Epoxy would be better IMHO if you can colour it (before or after) satisfactorily.

My sister does antique furniture restoration and that's what they were taught at TAFE.

Done correctly it is an invisible repair (holes , busted edges etc).

Rob

[angryranga]

clear epoxy

[gord104]

ok I will try epoxy..there are a couple of other factors that go with this..I am not trying to fill a hole I am trying to make a approx. 12x12 inch thick sort of boards this way....crazy yes..but to go ahead with what I am doing I need to figure this out..been working alot so will try epoxy this weekend and post the results
thanks guys

[soundman]

So ya reinventing the wheel and making chipboard:?

UM :hmm: WHY.

And doing so in sabs that big you are going to run into all sorts of problems because you probaly wont have the facilities to mould under pressure, and finding a resin that is stable in that size slab will be interesting.


OH BTW...Adquahere ( PVA) and sawdust is one of the worst wood fillers there is.
The idea of glue and sawdust worked well with hide glue, but it simply does not translate well with PVA that replaced it.

cheers

[GraemeCook]

Good Morning gord104

Over the years I have had excellent results with epoxy and saw-dust or sander-dust. In fact, whenever I am sawing or sanding some particular good timber I save the dust - a jar for each type, course & fine. My preferred epoxy is WEST System slow hardening - a good Canadian product - or the local fibreglass shops generic copy thereof. You will probably also need a mold release agent, if you are casting your "boards".

In mixing such large quantities of epoxy, heat build up may be quite a problem - it may get out of control - so heed the safety instructions very carefully.

The best book on epoxy usage - boat specific - is "The Gourgeon Brothers on Boat Construction - WEST System." published in Canada and probably in your local library.

Fair Winds

Graeme

[Master Splinter]

The best book on epoxy usage - boat specific - is "The Gourgeon Brothers on Boat Construction - WEST System." published in Canada and probably in your local library.


Mmmmm my bible.......
http://www.westsystem.com/ss/assets/HowTo-Publications/GougeonBook%20061205.pdf

[tea lady]

In actual chip board they use resorsinol. :shrug: That would prolly work.

[soundman]

Putting sawdust, chips or shavings in epoxy or another suitable resin may be a good thing:2tsup: for filling smallish holes up to bigish cavities in a workpiece.

But it seems the OP is talking about laying up slabs of the stuff, that is where it starts to get hard.

All the manufactured boards such as plywood, chipboard, OSB board and masonite have relativly low amounts of resin compared to timber material and all are laid up and cured under pressure.

Likewise many of the slab plastics and laid up and cured under pressure.

As soo as you start pouring big slabs of mix & pour resins, there are all sorts of problems.

We realy need to know what he is trying to achieve.

cheers

[GraemeCook]

Putting sawdust, chips or shavings in epoxy or another suitable resin may be a good thing:2tsup: for filling smallish holes up to bigish cavities in a workpiece.

But it seems the OP is talking about laying up slabs of the stuff, that is where it starts to get hard.

All the manufactured boards such as plywood, chipboard, OSB board and masonite have relativly low amounts of resin compared to timber material and all are laid up and cured under pressure.

Likewise many of the slab plastics and laid up and cured under pressure.

As soo as you start pouring big slabs of mix & pour resins, there are all sorts of problems.

We realy need to know what he is trying to achieve.

cheers

This isn't new technology. The relatively high ratio of epoxy to sawdust mixture is fairly commonly used in boat building to cast plinths in-situe for winch bases, jammer bases, cleat bases, etc. There must be sufficient epoxy that one is absolutely sure that the sawdust is fully wet through throughout the casting. The finished product is sort of like a semi translucent bakelite; when cured it can be filed, sanded and painted. Gord104 just wants to take the process one step further.

But for large casting heat build up and accelerated setting is an issue - hence my safety warnings.

Fair Winds

Graeme

[soundman]

I am well aware that there are people casting all sorts of things in polyester, epoxy and other resins...and sucsessfully.

But my concern is the shape and proportions that are proposed to cast...smallish blocks that are relativly thick in comparison to their size would be much more stable.

A large flat thing a foot square and an inch thick would be more of a challenge and require some carefull thaught and choice of resins.

Depending on what he is trying to achieve, there may be better, easier and cheaper ways of acheving it than trying to cast it in one big lump

These things aint going to be cheap either.....I cant see it taking any less than half a litre of resin.....if that resin is marine epoxy or polyeurathane that will be getting expensive.

cheers

[GraemeCook]

You are absolutely right, Soundman.

That foot x foot x inch board that you hypothesise is about 2.25 litres gross. Depending on sawdust ratio it could take even more than ½ litre of epoxy - and epoxy is expensive.

Current prices for the stuff I use (a WEST reverse-engineered) is:


½ litre - $25 = $50 per litre
4 litres - $99 = $25 per litre
20 litres - $399 = $20 per litre

Fair Winds

Graeme