Polyester verses polyurethane resin

[sfurini]

My experience of the two different resins is that PU is easier to turn and threading it is much easier than threading PR - in fact, my attempts at threading PR have all failed so far! Probably down to my technique. PU threads like a dream though. If making a kit pen then PR is as good as PU, granted that you have to cut them differently. For a kitless pen I go with PU.

 

[Bammer]

I am so confused with all this PR / PU abbreviations .... perhaps it's too early in the morning ...

Is there a list / table or something where this is all laid out ?

 

[Woody]

What a load of cobblers you can see he intended to prove one material over the other all different materials need to be treated differently including woods some are more stubborn than others to turn but that's half the fun of turning and you can get an excellent finish on all of them as has been proved on this forum with all the different materials that have been turned and shown any idiot can do what that plank done the same applies to wood some will crumble when worked some are as hard as nails you just find the best way to turn each one well a turner worth his salt would

 

[Lons]

What Woody said

I can't speak with the same authority when it comes to pens and I have absolutely no experience of the black art of casting your own but my day job from many years ago provided me with a plentiful supply of offcuts and samples of most of the commercially available semi-finished plastics in sheet, block, tube and rod forms and I have over the years worked with as well as turned virtually all of them.
Like any other material you work with they need techniques to suit, after all you wouldn't turn a block of pine in the same way as you wood a piece of lignum vitae wothout coming to grief.

Plastics have different hardness, resilience, melting points etc and in normal working they aren't especially hazardous, certainly no more so than many hardwoods unless breathing in sanding dust which you shouldn't be or burning in which case sharpening lessons are desperately needed. Even burning won't harm anyone unless breathing in a lot of the fumes and burning a corner of an unidentified bit of plastic is often the surest way to determine what it is by the smell it gives off. You need a practiced nose to do that.

 

[bassethound]

What a bloody stitch up video! the mans a nutter

 

[bluntchisel]

As Woody says, it's horses for courses, ennit!

Bob.

 

[Penpal]

With the thin veneer of wood on some expensive kits the collateral damage tossing them around would be a disaster but comparing apples with apples seems fairer, I believe this man is one hell of a good guy you all love his products and other research I know I do.

Peter.

 

[chas_41_uk]

I'm in agreement with Woody, Ted and the two Bobs. A very bias video

 

[puggy]

There will always be advantages and disadvantages to any type of plastic. Polyester is easier to cast as it's a slow setting resin, it dosn't need to be rushed, you don't need to use either a pressure pot or a vacum chamber as most of the bubbles will rise before it sets (and with more time to set you can mix it slower thus getting less bubbles in the first place). Yes it's more brittle than PU but then again i've lost a few drill bits as PU heats up and melts easier than polyester (some of the PU blanks out there can heat up and melt very quickly) and if you work an area too much for too long it will melt and bubble ruining the work you put in, which it hasn't (yet) happen to me with polyester.

In the end though i havn't seen anything to suggest one is better than the other when you compare the end product, the only difference is how you get to the end product is different with the various materials

 

[Jim]

That is bang on Darren .. I have lost PU several times due to it losing it's shape when over heating .. But the final result is what matters as you say ..

 

[21William]

I believe that you can introduce additives that make Polyester resin less brittle.

I wonder if this stuff is any good or whether it's too soft? It depends how much "flexible additive" there is in it!?

https://www.fibreglassdirect.co.uk/polyester-resins/roofing-resin.html