What is best material to use to make form blocks?  Regular plywood, MDX, regular lumber???

Views: 822

Reply to This

Replies to This Discussion


I've used 3/4" MDF so far.  Haven't had any problems with it.

I've made the rudder and am now making horizontal stabilizer parts. I made the (6) 6T1-2 Center Ribs over the weekend and the MDF held up just fine.

You're not making a huge number of parts with each block so not a lot of wear and tear.

My $0.02.


I used 3/4 inch plywood for the form blocks for my 701 and the blocks worked well.  I'm planning on scratch building a Cruzer next and will likely use plywood again but only because I have a bunch of scraps I got for free.  If I had to buy the material I would likely use MDF.

Doug M

I agree

I bought the Scratch Building Basics for Metal Aircraft DVD from homebuildhelp.com and got to know everything there was to know about form blocks, forming ribs, cutting and bending sheet metal and more in about 45 minutes :-)

Yes, Mark and David did a fantastic job on the Scratch Building Basics for Metal Aircraft video for Jon.  I recommend it even for those who are kit building as it gives you the confidence to replace a part if you make a mistake.

Thanks for all your replies.  I have a lot of scrap 3/4 inch plywood, and will use it for making the forms...

In case you have no luck w/ plywood: I used MDF, and applied two coats of varathane.

I suspect that without the varathane the MDF would not take the pounding well...

Good luck


I do not apply anything to the MDF and it holds up more than adequately for what needs to be done.

Give it a try without the varathane.


Thanks, I am reconfiguring my basement, building some additional benches and moving tools around.  I really liked how you mounted the vice to the plywood so it could be moved around. I am definitely going to use that idea....

I've had to make things modular and mobile for my workspace. I'm using my garage but need to be able to still park our cars there.

I'm glad one of my pictures gave you something that you could use!


I used 3/4" MDF for my CH650 forms except for the nose ribs, for them I used plywood but laminated 1/8" aluminum to the form so I could really work on the nose area and because of the amount of ribs I had to make with that form.  For the CH750 I just used plywood that I had, either material should be fine.  I did not seal my MDF forms with anything but made each form and then the ribs for that form as I did not know if expansion of contraction with humidity changes might occur.  

One note of caution, sawing, sanding MDF CREATES a LOT OF DUST.  I used a paper dust mask when building the forms


New from Zenith:

Zenith Planes For Sale 

Classified listing for buying or selling your Zenith building or flying related stuff...

Custom Instrument Panels
for your Zenith

Custom instrument panels are now available directly from Zenith Aircraft Company exclusively for Zenith builders and owners. Pre-cut panel, power distribution panel, Approach Fast Stack harnesses, Dynon and Garmin avionics, and more.

Custom Upholstery Kits for your Zenith Aircraft:

Zenith Vinyl Upholstery Kits

Zenith Apparel from EAA:

Zenair Floats

Flying On Your Own Wings:
A Complete Guide to Understanding Light Airplane Design, by Chris Heintz

Builder & Pilot Supplies:

How to videos from HomebuiltHELP.com

Developed specifically for Zenith builders (by a builder) these videos on DVD are a great help in building your own kit plane by providing practical hands-on construction information. Visit HomebuiltHelp.com for the latest DVD titles.

Aircraft Insurance:


West Coast USA:

Pro Builder Assistance:


Transition training:

Golden Eagle Aviation

Pianosa Flying Farm

Aircraft Spruce & Specialty for all your building and pilot supplies!

© 2020   Created by Zenith.Aero.   Powered by

Badges  |  Report an Issue  |  Terms of Service