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This information is based on the coaster workshop run by Christoff Epp. Members can add more details (especially tips and tricks please!) as required.
Safety
for all |
Epoxy Room/Precautions pulls into the tool portion of this page; maybe the tool template should pull this into the instruction portion instead. The idea is that when a whole room is affected by a hazard, we should really store it at the room level, and if it is stored at the room level, we shouldn't re-apply it at the tool level. |
Fumes - epoxy emits fumes, mould release is aerosolized, and isopropyl alcohol emits fumes. The LifeBreath ventilator runs automatically, and you should consider wearing N95 mask when spraying mould release.
Fire - members can use a torch to remove bubbles. Make sure there's nothing flammable nearby, hold the torch away from the benches and walls, and stay in the area for 30 minutes to watch for signs of fire.
Laceration - epoxy edges will be extremely sharp when removed from the mould, especially the top surfaces and interior holes. Use extreme caution when removing parts from moulds and round over the edges with sandpaper or a router as soon as possible.
Skin damage - epoxy is bad for your skin, as is isopropyl alcohol. Wear gloves at all times.
Eye damage - epoxy can splash when pouring and mixing. Wear goggles to protect your eyes.
If you get epoxy on your skin or eyes, flush thoroughly with water for 15 minutes.
Things You Shouldn't Do
- Use compressed air – it will blow dust everywhere and can ruin your/others’ projects
- Use chisels on HDPE molds – you will damage them and need to replace them.
- Forget mold release.
- Use communal paddles to mix pigmented resin – there are some available in the vending machine, or you can make your own mixer paddles.
Workspace preparation
It’s important to protect the workspace before you start. Dust can affect your project, as can non-level work surfaces. Additionally, dried epoxy will damage the work surface over time.
Currently, it is not possible to level any of the workbenches at North Forge but they will be levelled shortly. It’s a good idea to check the surface with a level before starting. If the bench is not level, you may decide to use shims underneath your mould.
Silicone mats are available for small projects. For larger projects or if there is a risk of dripping (shaky hands, natural human messiness) you can also cover the workbench with plastic wrap.
If you get epoxy on the work surface, do not panic. Either use isopropyl alcohol to clean it immediately, or if it has dried you can use a chisel to carefully scrape it with the blade nearly parallel to the table.
Cleaning - Isopropyl Alcohol
Epoxy can be cleaned using isopropyl alcohol. Do note that isopropyl alcohol will irritate your skin and eyes, and can ruin your project if you spill. For that reason, if epoxy spills on the outside of your mould, it’s best to let it dry and carefully remove it when done. How can you get it off if you spill on the outside of the HDPE moulds? Not OK to use chisels, can you bang or flex the mold slightly to remove?
Material preparation
Some materials are naturally porous and will release air when submerged in epoxy. Other materials will not stick to epoxy or will cause discoloration.
To prepare wood for epoxy, remove all bark because it will separate from the wood and ruin the project. Large cracks and knots will also release air, so remove large knots and pre-coat cracks with UVPoxy before starting. Sand the surface to 150 grit.
Consumables Information
Resin
North Forge has three types of epoxy available for members to buy:
UVPoxy: Quick-curing epoxy used for small pours (up to ¼” deep). Pot time is 30 minutes, cure time is 48 hours. It is mixed in a 1:1 ratio. How clear is this? How much will it cost?
SPR: Used for medium pours (up to 1.5” deep). Pot time is 4 hours, cure time is 2-3 days. It is mixed in a 2:1 ratio. How clear is this? How much will it cost?
FlowCast: Used for deep pours (up to 3”). Pot time is 8 hours, cure time is 3-7 days. It is mixed in a 2:1 ratio. How clear is this? How much will it cost?
Judging the amount of resin to mix is very difficult. It's also more difficult to mix small amounts of resin, so it's a good idea to prepare more than you think you will need. For this reason, Christoff recommends preparing a secondary project to use up any extras. Examples of good secondary projects include coasters, keychains, and jewellery. Christoff has also supplied several "wine butler" moulds (used for holding both wine glasses and assorted cocktail snacks in one hand, leaving the other free for gesturing, hand-shaking, and other assorted social activities).
Pigment
There is no specific way or formula to get a certain shade out of epoxy – you will have to experiment, use your judgement, and develop your own recipes.
Buckets
It is technically possible to reuse buckets/cups that have been used for clear epoxy, however buckets are so cheap that it's usually not worth it. The 5 gallon buckets are the exception.
Empty header? Costing and usage? Ask Christoff for details until this is filled out.
Mold Release
Mold release is very important to get good results and preserve the molds for future use. ALWAYS USE MOLD RELEASE on anything that will touch resin (except for the table/working mats).
Costs
Epoxy costs $0.30/mL (for all types?). Each job will also have a $2.50 surcharge to cover things like mould release, gloves. Costing for pigments and buckets? Ask Christoff for details until this is filled out.
Mixing
Mixing is usually done in two buckets: the first for mixing the two parts, and the second for pigments. Does Christoff also suggest pouring into a second bucket for clear (ie to prevent unmixed epoxy from going into the project)? When pouring from one container to the next, do not scrape the sides as that is where unmixed epoxy will gather.
It is not possible to reuse the first mixing bucket. It may be possible to reuse the second mixing bucket, however the low cost of buckets means it is usually not worth the effort (unless using 5 gallon pails).
To mix A and B parts, mix slowly until the swirls disappear. Be careful not to over-mix. Keep the paddle near the bottom of the bucket to avoid mixing in air, and avoid the sides of the bucket to avoid chipping and mixing in bits of plastic.
Please do not use communal paddles to mix pigmented resin. Note that the A and B parts can sometimes separate if left to sit for too long.
Fixturing
Many materials will float in epoxy and must be held down with clamps or other objects. Christoff has supplied a dovetail clamping fixture for members to use. Do not clamp directly onto the workpiece; instead, use HDPE blocks or other objects as a spacer. Don’t forget to spray anything that touches the epoxy with mold release before use. Also consider that you may need to use a torch to remove bobbles once the object is clamped in place. Some objects will react very poorly to being torched so consider that fact when choosing your fixturing method.
Molds
The Ecopoxy room has a a number of moulds available for use. Some are supplied by Ecopoxy/North Forge, others are supplied by our resin expert Christoff Epp. Note that if you damage any mould, you will be required to replace it. If you damage one of Christoff’s moulds, you will no longer be allowed to use them. Never use chisels or metal scrapers on any of the moulds.
There are two types of common moulds: HDPE and silicone. HDPE molds are rigid and are best for simple shapes like rectangles and circles (coasters, slabs, etc). Since they are rigid, they are more difficult to de-mould. Silicone moulds are more flexible and are better for more complex shapes. They also may wear out more easily than HDPE moulds, and can attract dust through static electricity. Other mould options are available including ones that are made by sealing the sides of the project; consult Christoff for advice if you’re not sure what to use.
Some molds may have discoloration along the edges. This is OK and will not affect your project, it’s caused by mould release that is not touched by resins.
Bubbles
Mixing and pouring resin naturally introduces bubbles into epoxy. Some materials may also have trapped air that will be released when the project is submerged. Bubbles can be removed by torching, using a vacuum degasser, or tapping/vibrating the mould (may be challenging and is more of a last resort).
Pre-use Checklists
- Gloves are worn
- Mask is prepared for use when spraying mould release
- Goggles are prepared for use when pouring and mixing
- Mould release has been applied
We might add more info here soon.
Releasing
If you’ve remembered to use mold release, most objects will come out very easily. If you’ve forgotten to use mould release with HDPE molds, you may be able to remove your object but it will probably take extreme violence. Do not drop HDPE moulds on the table as they will damage the table. Instead, wear hearing protection and hit the bottom of the mould with a hammer using as much force as possible.
Random Tips and Tricks
General
Dust is not usually a problem for pigmented projects, but it will show up in clear projects. Surface dust can sometimes be removed with a planer.
Always bypass the SawStop when cutting epoxy – it will set off the SawStop and you will have to pay for the new blade and cartridge.
When pouring in multiple phases, there are two options: either pour the second layer when the first is still slightly tacky, or wait until the first pour is cured then scuff with sandpaper. If you try to pour epoxy on a smooth cured layer, it will not stick.
Do not let epoxy get above 26 degrees. Use an IR thermometer when doing deep pours, and if it starts to heat up too much you can use a fan to lower the temperature.
You can laser-engrave epoxy, but it usually doesn’t produce good contrast. Instead, it will produce a frosted white appearance like when lasering acrylic.
It is also possible to use the CNC equipment to cut epoxy, but the fine dust will cling to all surfaces due to static electricity. In this case, you will have to do a cleanup immediately after the cut is complete, then return the next day to clean the remainder that was previously stuck to all surfaces but has since fallen.
When pouring from a jug, you should hold the jug with the opening towards you and pour over the top of the jug. This will prevent glugging.
UVPoxy
It is possible to over-mix UVPoxy, which causes micro-bubbles that cannot be removed. If this happens you will need to scoop out the epoxy and start over.
SPR
You can let SPR sit for a short time to heat, which will decrease the viscosity and make it easier to pour.
FlowCast
It’s sometimes a good idea to let FlowCast sit for 2 hours after mixing large quantities. Doing so will allow bubbles to rise to the top, plus the exothermic reaction decreases the viscosity and makes it easier to pour.