rgraves

I am building a 96" supercobra plug with the bulkhead and foam method, i added baby powder [what i thought was alot] to a sample piece of foam section let it cure,and sanded it. The powder did not seem to help much with the ease of sanding,any ideas on this would be appreciated. Thank you,Richard

Ed Smith

I do a lot of glass work. I have learned over the years that there is no cheap substitute for the correct material. Get rid of the baby powder and use micro-balloons. Now all sorts of people will probably jump in and refute this, advising you to use Talcum powder, baking soda and on and on. I rarely have problems with my composite work. I use the correct material.

Take my advice and use the correct material.

Ed S

P.S. Did I suggest using the correct material!

branded

My Feedback: (9)

This is the correct material as defined by you......

Ed Smith

I do not understand why your reaction to simple advice freely given is hostile, on this thread and another one. My advice to use correct material is based on my own experience of trying the cheaper alternatives. The correct material properly used will always work, the cheaper alternatives are always hit or miss.

I have several catalogs from suppliers of composite materials. They offer all sorts of cloth, resins and fillers. Strangely enough nowhere in the catalogs can I find baby powder.

The use of correct materials is not defined just by me. The usage is defined by those of us that actually use, not just talk, about the material, those of us with real experience.

Ed S

ChuckA

Ed is right. It's almost always cheaper to do it right the first time.

branded

My Feedback: (9)

No Ed, I just take exception to those that put out supposed "expert" information that runs contrary to the accepted methods used for many years by modelers; modelers that collectively and literally dwarf yours and my experience.

I take exception to your assertions that "use the right" materials, etc, when that's simply your opinion and doing so diminishes everyone elses opinion on the use of other methods, materials and processes.

Using talcum powder as an additive to thiken epoxy or WBP is a tried and true method, not hit and miss as once again you portray as the "wrong" way to do things.

I joined these discussions in a cursory way after a long lapse away from these forums but I see we have a whole new generation of guys disseminating misinformation on the internet.

It's not my intention to be argumetative but given you, and another user from another thread, don't have the intutive knowledge and skill to thin epoxy, that in itself makes me wonder aloud why you would want to pass along advice to the "masses" given your own ignornace of some of these process' ?????

Hope this helps...

PlaneKrazee

My Feedback: (14)

Easy to sand, micro balloons, glass or phenolic. Thickening agent, collodal silica.

dreadnaut

My Feedback: (5)

A corollary to this is; The fastest way to do a job, is to do it once.

fw190

My Feedback: (37)

I make composite molds and I confess to using TALCUM POWDER!

One - Its CHEAP!
Two - It helps fill the fiberglass weave on my 'flying models' and 'plugs' for final skin coating before primer.
Three - most importantly it makes the garage smell nice!

Also it might be safer to use than glass sphere... heck they use on babies! I can sprinkle that all over the garage without worries.

Now I don't use the talcum to make molds, I don't want to waste time and money.

Larry S

My Feedback: (6)

I have to confess to using baby power also. On another thread I told how I glass my planes, not how anybody else should do it. In the past after I sanded down the glass layer, I use to use Krylon primmer/sealer mixed with baby power to fill in the weave and that worked great, except when I went from using Cheveron paint to Nelson's. To get a good bond for your top coat, you have to use Nelson's primmer or a similar primmer. Nelson's won't bond with Krylon primmer very well, that I found out the hard way. Also with the Krylon primmer with baby power mixed in, I would spread it on the part with a foam brush which would leave a larger build up of material to sand but would sand very easily and would have to be done only once in most cases. With the Nelsons primmer, I guess I could try doing the same thing with a foam brush but lately I just spray on a light coat, sand and if necessary, do it again until I get the finish I want.
Larry

Kweasel

My Feedback: (29)

Micro balloons thicken and greatly decrease the density of that heavy epoxy.

Larry S

My Feedback: (6)

Kweasel,
I found that out. I haven't used micro balloons much until lately and I do like the way it works to fill in areas. I used micro balloons on a Jemco corsair at the wing joints and I liked the way it worked. Was much easier to sand then I would have thought at first and it spread out pretty good although I had to use a little more micro balloon in my second batch as the first batch I mixed did settle some. I used it where the wing on the corsair comes to a bend to make a nice round shape. I can see using micro balloons does a nice job of filling but a lousy job of binding for strength.
Larry