which blade?

[journeyman]

hi all
I'm wanting to make some stuff from 6mm MDF. What is the best blade to use. ie:- TPI
Not making anything fancy. Just thought I'd make a puzzle for my grandaughter for my first project.

 

[chrispuzzle]

With puzzles, it depends how tight the turns are. You'd probably be fine with a size 1 for big chunky puzzle pieces but for small puzzle pieces of the sort of size you'd expect in a standard jigsaw puzzle from a shop you would be struggling unless you used the finest 2/0 blades. You do not need a butch, aggressive blade for 6mm MDF, it's easy to cut with fine blades.

Mike at Flying Dutchman, and Hobbies of Dereham (via eBay), do assortment packs which give a range of types so you can try them out and have something to hand for the odd job that's not what you usually do.

 

[journeyman]

Thanks Chris
I've taken on board your advice and visited the sites you suggested. My blades are winging their way here as we speak. Have you any recommendations for sealer and paints for the finished job.
cheers
Mick

 

[chrispuzzle]

I use Rustins for a sealant but I haven't compared it to anything else. Seems to do the job. I confess that with paint I use what's to hand, that is, any paint that's OK for wood generally, but since nearly all my work is cutting jigsaw puzzles, I only use paint for the odd project.

You need to watch the cut edges with MDF though (as with most wood) as it is often more absorbent than the finished surface.

Someone else must have more MDF experience though?

 

[StevieB]

Gill is the MDF Queen but I havent seen her on here for ages despite being a mod for the scrolling board - think she has real life commitments at the moment. Could try a pm perhaps or do a forum search - I have a feeling she was using a lacquer from Wickes but could be completely wrong on that...

Steve.

 

[Gill]

I'm still around and lurking when I can, but not contributing much because of other commitments (as Steve surmises). Anyway, you guys seem to be doing fine without me .

I concur with Chris' comments about blade selection. The smaller the blade, the tighter the pieces will fit together. However, it's very easy for inexperienced scrollers to break finer blades, so make sure you've got plenty of replacements to hand! I'm a fan of skip tooth blades, especially with MDF which produces a fine dust as it is cut. This dust can clog up normal blades. It won't do you much good if you inhale it either, so breathing protection is strongly recommended.

For a child's puzzle, a #1 blade should be adequate although I would be concerned that the cut edges of the MDF might not be durable. After all, MDF is little more than glorified cardboard and after the puzzle has been used a few times it will show greater wear than if it had been cut from wood.

I like to brush on Wickes acrylic primer/undercoat to seal MDF (or wood) before I paint it. If you can't get any of that locally, search around on this board for gesso and you should find a link to a supplier of a similar albeit slightly more expensive alternative. You'll have to apply at least a couple of coats and sand between coats depending on how porous and 'flaky' the MDF is. The primer will dry within twenty minutes to a white, matt finish which can then be painted with your choice of topcoat - acrylic, oil-based or whatever .

Gill (who's now experiencing serious workshop-withdrawal symptoms )

 

[journeyman]

thanx Gill
Your advice is very welcome. I am new to scrolling and as I have plenty of mdf left over from other woodworking projects thought it would be a cost affective way to get in some practice. I have a local Wickes store which I use from time to time so I will be calling in there.
You're absolutely right about mdf dust, it can be really nasty. I do quite a bit of routing with mdf and have made my own extraction system from an old Dyson. Even so I always wear a mask as well.