1. Technical Information - Adhesives

 

1.1. CA - What is it?

Question: I see the term "CA" mentioned here, what do you mean by CA?

Answer: CA is short for CyanoAcrylate or short for Cyanoacrylate Adhesive depending on who you talk to. Both are correct. CA is the family of adhesives that is often described as "Super Glue".

CA's cure quickly, glue a wide range of materials and provide a very strong bond even in small amounts.

 

1.2. CA's - Should they be stored in a Fridge?

 

Question: Should CA's be stored in a refrigerator?

Short Answer:  Good quality CA's like the Pacer ZAP line do not require refrigeration unless you plan on storing the product for more than a year. Keep the bottle sealed and out of direct sunlight or hot rooms. If you do refrigerate any CA, allow it to stabilize and come to room temperature overnight before using.

Better Answer: There has long been a controversy over the need to refrigerate CA's in order to sustain their shelf life. It is helpful to understand the history of this practise, the original reasons for it and what we recommend today.

1) Background.

Refrigeration slows down the decay of CA's and subsequent hardening caused by contaminants in the glue, evaporation of additives, UV light, water vapour and poor packaging. Prior to 1982, most CA's offered into the hobby market, were in fact industrial products that had failed against some factory criteria. Hobby "packagers" would buy this discarded material and package it for consumer sale. In many cases, the shelf life of the material was 60-90 days and if you wanted to extend the life, refrigeration was required. This practise continues today for adhesives sold at the lower end of the price scale.

2) In 1982...

Pacer Technology introduced the ZAP line of adhesives that were blended and formulated specifically for consistency, quality and long shelf life. Pacer also introduced nitrogen bottle purging and filling, welded bottle nozzles and CA's that were more pure than anything on the market up to that time. Unopened shelf life was guaranteed to the purchaser for 1 year.

3) Today...

Only the low cost cheap grade CA's require refrigeration in order to extend their shelf life longer than 90 days. Good quality CA's such as ZAP (Pacer) products are made from the purest materials, packaged to ensure long shelf life and do not require refrigeration.

4) If refrigeration is undertaken...

There are several issues to concern yourself with. Let the adhesive come to room temperature overnight before using. Cold glue is slower to cure, offers weaker bonds and condenses water from the air as room temperature air is sucked back into the bottle to replace cold glue dispensed. The warmer air condenses over the cold glue remaining in the bottle. This addition of condensed water further contaminates the glue and dramatically shortens the life of the remaining CA in the bottle.

1.3. CA's - Thin, Thick or Very Thick? Which to use for what?

 

Question: What is the difference between the various thicknesses of CA's? Some are thin like water, others are thick like syrup or molasses. Which is to be used for what? 

Short Answer:

- Thin CA offers the fastest cure, can be applied after parts are assembled, parts MUST fit well, and thin CA is reasonably tolerant of different wood types

- Thick CA offers fast cure, must be applied to the parts prior to assembly, some roughness of fit is OK and thick CA is very tolerant of different wood types.

- Very Thick CA offers a slower cure, must be applied to parts prior to assembly, can be applied to parts that fit poorly, can be used like a white or aliphatic glue and very thick CA is tolerant of different wood types.

Better Answer:

1) Thin... almost like water (typical viscosity 5 centipois).

- works well on pure woods and plastics (except Teflon, Delrin or Nylon) that fit very well. There should not be a gap between the parts. The wood should not be pitchy or laminated like plywood. - does not work well on pitchy wood, dirty parts, rough fitting parts or parts that are extremely porous. - cure time is almost instant, in the order of seconds - parts should be assembled first and the adhesive wicked into the joint externally. The adhesive will penetrate many millimetres and up to a centimetre into the joint area. - great for assembling open frameworks like model airplane wings that can be fitted together, pinned into position and then glued together when ready. Just apply a drop to each joint area, wait a few moments and you can remove pins etc and you are done! - do NOT use thin CA with CA accelerators. - typical brand names, ZAP with a Pink Label, VCA with a Red Label.

2) Thick sometimes called Medium... like warm syrup (typical viscosity 100 centipois).

- works well on all woods and plastics (except Teflon, Delrin or Nylon) that fit reasonably well. Parts should fit well but will tolerate some roughness of fit. - Tolerant of pitches, veneers and plywoods. Works well on hardwoods. Tolerates some porosity of substrates. - cure time is related to tightness of fit. Generally cures in 10 seconds when parts fit well. Up to a minute for rough joints. May take even longer to cure in open puddles. In all cases, application of accelerators like Zip Kicker and VCA Velocity speed up cure. - parts should be trial fitted first to ensure a good fit. Parts should then be separated and thick CA applied to one surface like white glue. the parts then can be fitted and secured in place to allow the adhesive to cure.  The adhesive will penetrate slightly into the substrates but not enough to allow for wicking after the parts have been assembled. External application will produce a fillet along the joint that does add strength to the joint but should not be the main adhesive joint. - great for assembling model airplane fuselages, hardwood bearers, plywood components, boats, veneers and most plastics. Probably the best all round choice if you must choose only one adhesive. - recommended for use with CA accelerators. - typical brand names, ZAP-A-GAP with a Green Label, VCA with a Green Label.

3) Very Thick... like white glue or aliphatic glue (typical viscosity 700 centipois).

- works well on all woods and plastics (except Teflon, Delrin or Nylon). Parts should fit but will tolerate considerable roughness of fit and gaps of up to a millimetre. - Tolerant of pitches, veneers and plywoods. Works well on hardwoods. Tolerates considerable porosity of substrates. - cure time is related to tightness of fit. Generally cures in 20 seconds when parts fit well. Up to a couple of minutes for rough joints. Will take longer to cure in open puddles. In all cases, application of accelerators like Zip Kicker and VCA Velocity speed up cure. - parts should be trial fitted first to ensure a good fit. Parts should then be separated and very thick CA applied to one surface like white glue. The parts then can be fitted and secured in place to allow the adhesive to cure. The adhesive will penetrate only slightly into the substrates and not enough to allow for wicking after the parts have been assembled. External application will produce a fillet along the joint that does add strength to the joint but should not be the main adhesive joint. - great for assembling model airplane fuselages, hardwood bearers, plywood components, boats, veneers etc. Great if you want the speed of a CA while using assembly methods applicable to white glue. - strongly recommended for use with accelerators. - typical brand names, SLOW ZAP with a Yellow Label, VCA with a Blue Label. 

1.4. Data Sheets - MSDS (Material Safety Data Sheet) & PDS (Product Data Sheet)

Question: I require data sheets (MSDS and/or PDS) for your adhesive products. How do I get them?

Answer: Please go to: https://supergluemsds.com and then...

Click the down arrow to the right of "Please Choose Product Brand",

or

Click the down arrow to the right of "Please Choose Product Name",

and then

Click Search MSDS for Material Safety Data Sheets,

or 

Click Search PDS for Product Data Sheets.  
 

 

1.5. Epoxy - Slow Cure vs Fast Cure - Which is Best?

Question: Epoxy is available in different cure speeds. Should I use a Slow Cure (30 Minute) or a Fast Cure (5 Minute) Epoxy?

Short Answer: Use 30 Minute Epoxy where strength and structural integrity is important such as when joining wings or mounting stabilizers, engine firewalls etc. Use Fast Cure for quick repairs of small non-critical components or joints. If in doubt, always use 30 Minute Epoxy.

Better Answer: There are two general factors to consider,  Bond Strength and Working Time. 30 Minute Epoxy creates a stronger bond and it gives you more time to work. 5 Minute Epoxy gives a good bond but it is not as strong as 30 Minute Epoxy and it must be used very quickly, particulary in warm conditions.

The Bond Strength is pretty straighforward... 30 Minute simply gives stronger bonds. Use 30 Minute when joining wings, installing stabilizers, engine firewalls or other load bearing critical structural components that you simply cannot afford to have come off or fail. Use 5 Minute Epoxy for quick minor repairs of non-load bearing or light load bearing less critical components.

The Working Time is something that modelers frequently overlook and tend to err a bit in favor of  "fast is good". In some cases, like a quick repair of a simple small component... fast is really nice! But in cases where the amount of adhesive is considerable, the components are large or complex and/or need to be simultaneously mated with other parts.... you need to allow for plenty of time to work in order to get the parts aligned and properly placed. It is very important that the Epoxy is fully "wet" when being used. If Epoxy starts to thicken at all before the parts are joined, the Epoxy will not produce a good bond.

The worst possible scenario is using 5 Minute Epoxy on a complex multi-piece job like joining a wing. We have had too many calls from people who end up with the Epoxy beginning to cure before the wing halves are properly joined. We have also seen wing joints after in flight failures caused by gummy thick half cured Epoxy not penetrating and filling the joint and component substrates properly.

If you have any doubts about the complexity of a job, need for strength, working time etc, always use 30 Minute Epoxy!