Flaring flange to plug

General Composites Discussions Composites Talk
#1

Hello all,

I’m new to the forum. I have made a few composite parts in the past ranging from wet lay to prepreg (school project). I have just setup a workshop and have a new project!

More on point:
I have prepped my plug and constructed a wide flange around it. I now want to flare the plug to flange with clay. I plan to roll up some long cylinders of clay, push it into the groove between plug and flange, then gently scrape or form the clay with a plastic straight edge. My concern is the scraping of the plastic edge on my prepped plug. Will I locally remove wax at the contact point from dragging the plastic across the plug?

Is that clear?

#2

So the flange is a secondary tooling fixture? Either way, if you are trying to attach mold parts together, and use clay to get rid of the flash line, then I think it should work. Your worry shouldn’t be a problem as long as your mold is made well, the plastic scraper isn’t the toughest plastic, and you are gentle. If all else fails, just recoat that area with more wax?

#3

Not exactly. Let’s be clear with terminology, there is no mold here yet. I have attached flanges to my plug, they are a different material. Before attaching the flanges I prepared my plug with wax. Now to bridge the gap between plug and flange I am using clay. When applying the clay I will have to scrape against the prepped plug and flange, forming the clay between the two. My concern is removing wax from the plug when scraping against it.
To illustrate, an extreme is using a metal straight edge, it would cut into the plugs surface exposing fresh material. I am guessing scraping with a plastic tool is quite the opposite and I will not remove wax. That’s my question.

#4

What you are doing is very common. No problem with that method. You’ll soon realize how tricky it is to get a good finish on clay even using steel slicks! It may look perfect on the plug, but small defects will still show on the mold surface and may need to be sanded smooth.
Just wax the areas again when the plug is complete. Don’t trust that any wax is still there regardless of how soft the scrapers are.

#5

Thanks fellas

#6

uh yeaaaah. I totally missed on my reply :slight_smile:

#7

I am placing this question here due to the relevance, rather than starting a new post.

I am making my first 2 part mold. I have a plug (it’s glass) and used craft board as a flange. The craft board is covered with aluminium foil tape and I have clayed the gap between the glass and craft board/foil tape. The plug is curved so it was difficult to get perfect registration of the aluminium foil tape against the curvature of the glass. I have clayed as best I can but it is clearly not perfect when you look very close. As soon as I address one slight imperfection I seem to cause another nearby. Will this affect the part line or will the slight imperfections ‘key’ against the second mold part?

Will I need to wax, or just use a liberal coating of PVA? [I am guessing glass and aluminium foil tape surfaces may assist minimising the release issues] If I need to wax, is there a risk during the wax application and polishing off, that it would affect the modelling clay surface? This question is especially pertinent to a notable feature on the plug is developed with modelling clay. What is required for release agent on a clay feature which is 15 or so mm across the plug?

I’ll try to get pics up later today.

#8

Use wax, throw PVA in a trash can, be careful with clay features as they don’t need wax.