Graham Orm
Established Member
lurker":3463al0t said:
Fair enough, thanks for the info. It's good to know, even so, all dust is to be avoided.
Material for Jigs?
- Thread starter Geofract
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Fair enough, thanks for the info. It's good to know, even so, all dust is to be avoided.
dc_ni
Established Member
Graham Orm
Established Member
Quote from the HSE document in the link added by dc_ni above :-
"What are the dangers of working with MDF compared with softwoods, hardwoods or other panel products?
The atmosphere created by machining or sanding MDF board contains a mixture of softwood dust and hardwood dust (if it is present). In addition, there will also be free formaldehyde, dust particles onto which formaldehyde is adsorbed and potentially, the resin binder itself and its derivatives. However, the levels of free formaldehyde in boards made within the EU at levels of formaldehyde class E1 are thought to be insignificant. This is because at these levels the resin is fully reacted (polymerised) – see Q.4 & Q.5 for information on standards and classes.
Under current legislation softwood dust, hardwood dust and formaldehyde are considered to be hazardous to health. Both softwood and hardwood dusts are known to be respiratory sensitisers and may cause asthma and other respiratory problems. Hardwood dust can also cause a rare form of nasal cancer.
Formaldehyde is classified in the UK, and in the European Union as a carcinogen and it carries the hazard statement ‘suspected of causing cancer’."
"What are the dangers of working with MDF compared with softwoods, hardwoods or other panel products?
The atmosphere created by machining or sanding MDF board contains a mixture of softwood dust and hardwood dust (if it is present). In addition, there will also be free formaldehyde, dust particles onto which formaldehyde is adsorbed and potentially, the resin binder itself and its derivatives. However, the levels of free formaldehyde in boards made within the EU at levels of formaldehyde class E1 are thought to be insignificant. This is because at these levels the resin is fully reacted (polymerised) – see Q.4 & Q.5 for information on standards and classes.
Under current legislation softwood dust, hardwood dust and formaldehyde are considered to be hazardous to health. Both softwood and hardwood dusts are known to be respiratory sensitisers and may cause asthma and other respiratory problems. Hardwood dust can also cause a rare form of nasal cancer.
Formaldehyde is classified in the UK, and in the European Union as a carcinogen and it carries the hazard statement ‘suspected of causing cancer’."
I've used MDF and I found the dust atrocious and the jigs I made with it sagged or got bent, including two table saw sleds, both got warped as bananas. Fortunately I have access to cheap birch plywood via my work, 3x12mm and 3x18mm full sheets for 100 euros isn't bad. Only B/BB grade with patches, and IIRC I might have found a cavity once or twice, but it has as many laminations as proper baltic birch plywood.
lurker
Le dullard de la commune
I was trying to get this in context. The cancer thing is very unlikely.
COPD ( look it up) from respirable dust is of a far greater magnitude , I'd guess a thousand fold
So..........if you take the same precautions with mdf as you ought to be doing with other woods the risk is not significantly different
Believe me cancer should be very low on our , as woodworkers, list of concerns.
There are people on this forum who have become so sensitised to certain wood they have had to pack it in.
And before anyone mentions the high Wycome throat cancer clusters yes I am aware, as they formed part of my thesis
COPD ( look it up) from respirable dust is of a far greater magnitude , I'd guess a thousand fold
So..........if you take the same precautions with mdf as you ought to be doing with other woods the risk is not significantly different
Believe me cancer should be very low on our , as woodworkers, list of concerns.
There are people on this forum who have become so sensitised to certain wood they have had to pack it in.
And before anyone mentions the high Wycome throat cancer clusters yes I am aware, as they formed part of my thesis
I''ve got a few jigs made from 12mm and 18mm MDF, all made from off-cuts. They work a treat.
mseries
Established Member
Years ago when I was starting out I made a tenon jig which was basically a box with a 6mm MDF top screwed to two sides which where inturn screwed to a contiboard base. I worked indoors at the time. Years later after I was forced to relocate to the garage I reused the jig and found my tenons were not parallel. The MDF had swelled and bowed. Same thing may have happened with other organic material I suppose . I keep saying I am going to seal 'wooden' jigs somehow but rarely do, I just make another if it goes pear shaped !
finish_that
Established Member
Commercial grade ie. thick laminate flooring is worth looking for jig material - very tough and slippery faces
plus you can laminate.. it to make thicker stock.
plus you can laminate.. it to make thicker stock.
Steve Maskery
Established Member
It's horses for courses. Do you want it to be slick and slippery (UHMW)? Do you want it to be cheap (MDF)?
MDF is my first call, and if an idea works I might remake it in MRMDF. A really successful idea might be remade again in phenolic.
I'd like to make my tenon jig in phenolic. But it all depends on how much time/money/effort you want to invest in an idea.
S
MDF is my first call, and if an idea works I might remake it in MRMDF. A really successful idea might be remade again in phenolic.
I'd like to make my tenon jig in phenolic. But it all depends on how much time/money/effort you want to invest in an idea.
S
condeesteso
Established Member
Steve Maskery":3ql9os53 said:
Totally agree, mdf is excellent for most uses - of course we all know it isn't stiff but it's easily braced. It's cheap, fast to work precisely, clean edges etc. Benefits from a quick seal - acrylic is very good for locking the fibres down (edges) and dries in minutes. Obviously ply is stiffer, so it depends on application surely.
And mdf emits a funny smell when machined - something that definitely isn't soft or hardwood, more chemical.
custard
Established Member
lurker":1aq802wh said:
http://www.hse.gov.uk/woodworking/faq-mdf.htm
Carcinogenic or not, I'd rather not get any in my lungs!
custard
Established Member
Different jigs may perform better in different materials.
MDF is stable and has a uniform thickness. It's easily crushed, doesn't take fastenings well (although there are workarounds to this), and sags under its own weight.
Plywood is more stable than solid wood, but it's rarely all that flat and thickness can vary even within a single sheet. It takes fastenings fairly well and is quite a bit more rigid and robust than MDF.
I'll use both materials for jigs, for example the base of my long veneer shooting board is MDF because above all else I want flatness, I just know to treat it carefully to guard against crushing the corners (if it was a jig in a shared workshop I'd put a hardwood lipping on). The base board for the jigs I use to form curves on a spindle moulder are ply, because I'll be screwing holdfast clamps into it and they need to be well secured, the actual master profile that I'll be copying from is MDF because that's more easily shaped to a smooth fair curve.
Think about what you want the jig to do then choose materials accordingly.
MDF is stable and has a uniform thickness. It's easily crushed, doesn't take fastenings well (although there are workarounds to this), and sags under its own weight.
Plywood is more stable than solid wood, but it's rarely all that flat and thickness can vary even within a single sheet. It takes fastenings fairly well and is quite a bit more rigid and robust than MDF.
I'll use both materials for jigs, for example the base of my long veneer shooting board is MDF because above all else I want flatness, I just know to treat it carefully to guard against crushing the corners (if it was a jig in a shared workshop I'd put a hardwood lipping on). The base board for the jigs I use to form curves on a spindle moulder are ply, because I'll be screwing holdfast clamps into it and they need to be well secured, the actual master profile that I'll be copying from is MDF because that's more easily shaped to a smooth fair curve.
Think about what you want the jig to do then choose materials accordingly.
Job and Knock
Established Member
For routing acrylic is better (especially as you can get offcuts for peanuts from signwriters), Tufnol (re-inforced phenolic plastic) better yet and HPL (high pressure laminate - think toilet cubicle walls, changing rooms, etc - another form of phenolic) is best of all IMHO. The dusts off all of these is pretty nasty, though, not good for the lungs
As for MDF - with "E1" the formaldehyde level is less than it is on pine - although the Daily Mail would have folk believe it's the next killer asbestos. The issue with it is the fine dust - and fine dusts can cause all sorts of respiratory problems.
As for MDF - with "E1" the formaldehyde level is less than it is on pine - although the Daily Mail would have folk believe it's the next killer asbestos. The issue with it is the fine dust - and fine dusts can cause all sorts of respiratory problems.
stuartpaul
Established Member
There is always a need to be careful with such sweeping statements as 'it's carcinogenic'. This can lead to massive and uncalled for over-reaction (e.g. mdf banned in schools).
It's also worth remembering that virtually all HSE limits are based on a time weighted average (TWA) of an 8 hour working day. Thus, most diyers are unlikely to come anywhere near any of the limits. Full timers need to be much more careful and consider the occupational exposure standards.
That said all dusts are an issue and care needs to be exercised.
It's also worth remembering that virtually all HSE limits are based on a time weighted average (TWA) of an 8 hour working day. Thus, most diyers are unlikely to come anywhere near any of the limits. Full timers need to be much more careful and consider the occupational exposure standards.
That said all dusts are an issue and care needs to be exercised.
iNewbie
Established Member
Anybody tried this Panzerholz link
Graham Orm
Established Member
Expensive I imagine
